diff --git a/browser/base/content/browser.css b/browser/base/content/browser.css
index 3cb7c4eddf47..857652c39a2c 100644
--- a/browser/base/content/browser.css
+++ b/browser/base/content/browser.css
@@ -599,6 +599,10 @@ toolbarbutton.bookmark-item {
   #personal-bookmarks[cui-areatype="toolbar"] > #bookmarks-toolbar-placeholder > .toolbarbutton-icon {
     image-rendering: -moz-crisp-edges;
   }
+  /* Synced Tabs sidebar */
+  html|*.tabs-container html|*.item-tabs-list html|*.item-icon-container {
+    image-rendering: -moz-crisp-edges;
+  }
 }
 
 #editBMPanel_tagsSelector {
diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
index 981a29651986..fd785de5d8a2 100644
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -6443,13 +6443,14 @@ function checkEmptyPageOrigin(browser = gBrowser.selectedBrowser,
   }
   // Not all principals have URIs...
   if (contentPrincipal.URI) {
+    // A manually entered about:blank URI is slightly magical:
     if (uri.spec == "about:blank" && contentPrincipal.isNullPrincipal) {
       return true;
     }
     return contentPrincipal.URI.equals(uri);
   }
   // ... so for those that don't have them, enforce that the page has the
-  // system principal (this matches e.g. on about:home).
+  // system principal (this matches e.g. on about:newtab).
   let ssm = Services.scriptSecurityManager;
   return ssm.isSystemPrincipal(contentPrincipal);
 }
diff --git a/browser/base/content/nsContextMenu.js b/browser/base/content/nsContextMenu.js
index af498a920052..e3b11da26bc8 100644
--- a/browser/base/content/nsContextMenu.js
+++ b/browser/base/content/nsContextMenu.js
@@ -564,12 +564,18 @@ nsContextMenu.prototype = {
     LoginHelper.openPasswordManager(window, gContextMenuContentData.documentURIObject.host);
   },
 
-  inspectNode: function CM_inspectNode() {
+  inspectNode: function() {
     let {devtools} = Cu.import("resource://devtools/shared/Loader.jsm", {});
     let gBrowser = this.browser.ownerDocument.defaultView.gBrowser;
-    let tt = devtools.TargetFactory.forTab(gBrowser.selectedTab);
-    return gDevTools.showToolbox(tt, "inspector").then(function(toolbox) {
+    let target = devtools.TargetFactory.forTab(gBrowser.selectedTab);
+
+    return gDevTools.showToolbox(target, "inspector").then(toolbox => {
       let inspector = toolbox.getCurrentPanel();
+
+      // new-node-front tells us when the node has been selected, whether the
+      // browser is remote or not.
+      let onNewNode = inspector.selection.once("new-node-front");
+
       if (this.isRemote) {
         this.browser.messageManager.sendAsyncMessage("debug:inspect", {}, {node: this.target});
         inspector.walker.findInspectingNode().then(nodeFront => {
@@ -578,7 +584,13 @@ nsContextMenu.prototype = {
       } else {
         inspector.selection.setNode(this.target, "browser-context-menu");
       }
-    }.bind(this));
+
+      return onNewNode.then(() => {
+        // Now that the node has been selected, wait until the inspector is
+        // fully updated.
+        return inspector.once("inspector-updated");
+      });
+    });
   },
 
   // Set various context menu attributes based on the state of the world.
diff --git a/browser/base/content/sanitize.js b/browser/base/content/sanitize.js
index 2639489cd926..943ff31f4d9f 100644
--- a/browser/base/content/sanitize.js
+++ b/browser/base/content/sanitize.js
@@ -111,7 +111,8 @@ Sanitizer.prototype = {
 
     // Store the list of items to clear, in case we are killed before we
     // get a chance to complete.
-    Preferences.set(Sanitizer.PREF_SANITIZE_IN_PROGRESS, JSON.stringify(itemsToClear));
+    Preferences.set(Sanitizer.PREF_SANITIZE_IN_PROGRESS,
+                    JSON.stringify(itemsToClear));
 
     // Store the list of items to clear, for debugging/forensics purposes
     for (let k of itemsToClear) {
@@ -677,10 +678,18 @@ Sanitizer.prototype = {
   }
 };
 
-// "Static" members
+// The preferences branch for the sanitizer.
 Sanitizer.PREF_DOMAIN = "privacy.sanitize.";
+// Whether we should sanitize on shutdown.
 Sanitizer.PREF_SANITIZE_ON_SHUTDOWN = "privacy.sanitize.sanitizeOnShutdown";
+// During a sanitization this is set to a json containing the array of items
+// being sanitized, then cleared once the sanitization is complete.
+// This allows to retry a sanitization on startup in case it was interrupted
+// by a crash.
 Sanitizer.PREF_SANITIZE_IN_PROGRESS = "privacy.sanitize.sanitizeInProgress";
+// Whether the previous shutdown sanitization completed successfully.
+// Note that PREF_SANITIZE_IN_PROGRESS would be enough to detect an interrupted
+// sanitization, but this is still supported for backwards compatibility.
 Sanitizer.PREF_SANITIZE_DID_SHUTDOWN = "privacy.sanitize.didShutdownSanitize";
 
 // Time span constants corresponding to values of the privacy.sanitize.timeSpan
@@ -766,6 +775,15 @@ Sanitizer.sanitize = function(aParentWindow)
 };
 
 Sanitizer.onStartup = Task.async(function*() {
+  // Check if we were interrupted during the last shutdown sanitization.
+  let shutownSanitizationWasInterrupted =
+    Preferences.get(Sanitizer.PREF_SANITIZE_ON_SHUTDOWN, false) &&
+    !Preferences.has(Sanitizer.PREF_SANITIZE_DID_SHUTDOWN);
+  // Regardless, reset the pref, since we want to check it at the next startup
+  // even if the browser exits abruptly.
+  Preferences.reset(Sanitizer.PREF_SANITIZE_DID_SHUTDOWN);
+  Services.prefs.savePrefFile(null);
+
   // Make sure that we are triggered during shutdown, at the right time,
   // and only once.
   let placesClient = Cc["@mozilla.org/browser/nav-history-service;1"]
@@ -786,18 +804,19 @@ Sanitizer.onStartup = Task.async(function*() {
   }
   placesClient.addBlocker("sanitize.js: Sanitize on shutdown", doSanitize);
 
-  // Handle incomplete sanitizations
-  if (Preferences.has(Sanitizer.PREF_SANITIZE_IN_PROGRESS)) {
-    // Firefox crashed during sanitization.
+  // Check if Firefox crashed before completing a sanitization.
+  let lastInterruptedSanitization = Preferences.get(Sanitizer.PREF_SANITIZE_IN_PROGRESS, "");
+  if (lastInterruptedSanitization) {
     let s = new Sanitizer();
-    let json = Preferences.get(Sanitizer.PREF_SANITIZE_IN_PROGRESS);
-    let itemsToClear = JSON.parse(json);
+    // If the json is invalid this will just throw and reject the Task.
+    let itemsToClear = JSON.parse(lastInterruptedSanitization);
     yield s.sanitize(itemsToClear);
-  }
-  if (Preferences.has(Sanitizer.PREF_SANITIZE_DID_SHUTDOWN)) {
-    // Firefox crashed before having a chance to sanitize during shutdown.
-    // (note that if Firefox crashed during shutdown sanitization, we
-    // will hit both `if` so we will run a second double-sanitization).
+  } else if (shutownSanitizationWasInterrupted) {
+    // Ideally lastInterruptedSanitization should always be set when a
+    // sanitization is interrupted, but some add-ons or Firefox previous
+    // versions may not set the pref.
+    // In such a case, we can still detect an interrupted shutdown sanitization,
+    // and just redo it.
     yield Sanitizer.onShutdown();
   }
 });
@@ -810,5 +829,8 @@ Sanitizer.onShutdown = Task.async(function*() {
   let s = new Sanitizer();
   s.prefDomain = "privacy.clearOnShutdown.";
   yield s.sanitize();
+  // We didn't crash during shutdown sanitization, so annotate it to avoid
+  // sanitizing again on startup.
   Preferences.set(Sanitizer.PREF_SANITIZE_DID_SHUTDOWN, true);
+  Services.prefs.savePrefFile(null);
 });
diff --git a/browser/base/content/tabbrowser.xml b/browser/base/content/tabbrowser.xml
index 091a67bfe9c6..3224de12a1ef 100644
--- a/browser/base/content/tabbrowser.xml
+++ b/browser/base/content/tabbrowser.xml
@@ -6243,9 +6243,11 @@
           if (browser.audioMuted) {
             browser.unmute();
             this.removeAttribute("muted");
+            BrowserUITelemetry.countTabMutingEvent("unmute", aMuteReason);
           } else {
             browser.mute();
             this.setAttribute("muted", "true");
+            BrowserUITelemetry.countTabMutingEvent("mute", aMuteReason);
           }
           this.muteReason = aMuteReason || null;
           tabContainer.tabbrowser._tabAttrModified(this, ["muted"]);
diff --git a/browser/components/feeds/WebContentConverter.js b/browser/components/feeds/WebContentConverter.js
index f8c7c36ba1cb..0c12583827c5 100644
--- a/browser/components/feeds/WebContentConverter.js
+++ b/browser/components/feeds/WebContentConverter.js
@@ -413,7 +413,7 @@ WebContentConverterRegistrar.prototype = {
     let notificationValue = "Protocol Registration: " + aProtocol;
     let addButton = {
       label: this._getString("addProtocolHandlerAddButton"),
-      accessKey: this._getString("addHandlerAddButtonAccesskey"),
+      accessKey: this._getString("addProtocolHandlerAddButtonAccesskey"),
       protocolInfo: { protocol: aProtocol, uri: uri.spec, name: aTitle },
 
       callback(aNotification, aButtonInfo) {
diff --git a/browser/components/migration/ESEDBReader.jsm b/browser/components/migration/ESEDBReader.jsm
index 74dc8de7cc9f..b94e2754ee6b 100644
--- a/browser/components/migration/ESEDBReader.jsm
+++ b/browser/components/migration/ESEDBReader.jsm
@@ -103,6 +103,9 @@ let gOpenDBs = new Map();
 
 // Track open libraries
 let gLibs = {};
+this.ESE = ESE; // Required for tests.
+this.KERNEL = KERNEL; // ditto
+this.gLibs = gLibs; // ditto
 
 function convertESEError(errorCode) {
   switch (errorCode) {
@@ -285,7 +288,10 @@ ESEDB.prototype = {
       ESE.SetSystemParameterW(this._instanceId.address(), 0,
                               2 /* JET_paramLogFilePath*/, 0, this.logPath);
 
+      // Shouldn't try to call JetTerm if the following call fails.
+      this._instanceCreated = false;
       ESE.Init(this._instanceId.address());
+      this._instanceCreated = true;
       this._sessionId = new ESE.JET_SESID();
       ESE.BeginSessionW(this._instanceId, this._sessionId.address(), null,
                         null);
diff --git a/browser/components/migration/EdgeProfileMigrator.js b/browser/components/migration/EdgeProfileMigrator.js
index c63cf6718713..b4eb8d5ffac4 100644
--- a/browser/components/migration/EdgeProfileMigrator.js
+++ b/browser/components/migration/EdgeProfileMigrator.js
@@ -52,15 +52,17 @@ XPCOMUtils.defineLazyGetter(this, "gEdgeDatabase", function() {
  * @param {function}          filterFn  a function that is called for each row.
  *                                      Only rows for which it returns a truthy
  *                                      value are included in the result.
+ * @param {nsIFile}           dbFile    the database file to use. Defaults to
+ *                                      the main Edge database.
  * @returns {Array} An array of row objects.
  */
-function readTableFromEdgeDB(tableName, columns, filterFn) {
+function readTableFromEdgeDB(tableName, columns, filterFn, dbFile=gEdgeDatabase) {
   let database;
   let rows = [];
   try {
-    let logFile = gEdgeDatabase.parent;
+    let logFile = dbFile.parent;
     logFile.append("LogFiles");
-    database = ESEDBReader.openDB(gEdgeDatabase.parent, gEdgeDatabase, logFile);
+    database = ESEDBReader.openDB(dbFile.parent, dbFile, logFile);
 
     if (typeof columns == "function") {
       columns = columns(database);
@@ -74,7 +76,7 @@ function readTableFromEdgeDB(tableName, columns, filterFn) {
     }
   } catch (ex) {
     Cu.reportError("Failed to extract items from table " + tableName + " in Edge database at " +
-                   gEdgeDatabase.path + " due to the following error: " + ex);
+                   dbFile.path + " due to the following error: " + ex);
     // Deliberately make this fail so we expose failure in the UI:
     throw ex;
   } finally {
@@ -221,33 +223,36 @@ EdgeReadingListMigrator.prototype = {
   }),
 };
 
-function EdgeBookmarksMigrator() {
+function EdgeBookmarksMigrator(dbOverride) {
+  this.dbOverride = dbOverride;
 }
 
 EdgeBookmarksMigrator.prototype = {
   type: MigrationUtils.resourceTypes.BOOKMARKS,
 
+  get db() { return this.dbOverride || gEdgeDatabase; },
+
   get TABLE_NAME() { return "Favorites" },
 
   get exists() {
     if ("_exists" in this) {
       return this._exists;
     }
-    return this._exists = (!!gEdgeDatabase && this._checkTableExists());
+    return this._exists = (!!this.db && this._checkTableExists());
   },
 
   _checkTableExists() {
     let database;
     let rv;
     try {
-      let logFile = gEdgeDatabase.parent;
+      let logFile = this.db.parent;
       logFile.append("LogFiles");
-      database = ESEDBReader.openDB(gEdgeDatabase.parent, gEdgeDatabase, logFile);
+      database = ESEDBReader.openDB(this.db.parent, this.db, logFile);
 
       rv = database.tableExists(this.TABLE_NAME);
     } catch (ex) {
-      Cu.reportError("Failed to check for table " + tableName + " in Edge database at " +
-                     gEdgeDatabase.path + " due to the following error: " + ex);
+      Cu.reportError("Failed to check for table " + this.TABLE_NAME + " in Edge database at " +
+                     this.db.path + " due to the following error: " + ex);
       return false;
     } finally {
       if (database) {
@@ -348,7 +353,7 @@ EdgeBookmarksMigrator.prototype = {
       }
       return true;
     }
-    let bookmarks = readTableFromEdgeDB(this.TABLE_NAME, columns, filterFn);
+    let bookmarks = readTableFromEdgeDB(this.TABLE_NAME, columns, filterFn, this.db);
     return {bookmarks, folderMap};
   },
 
@@ -388,10 +393,15 @@ EdgeBookmarksMigrator.prototype = {
 }
 
 function EdgeProfileMigrator() {
+  this.wrappedJSObject = this;
 }
 
 EdgeProfileMigrator.prototype = Object.create(MigratorPrototype);
 
+EdgeProfileMigrator.prototype.getESEMigratorForTesting = function(dbOverride) {
+  return new EdgeBookmarksMigrator(dbOverride);
+};
+
 EdgeProfileMigrator.prototype.getResources = function() {
   let bookmarksMigrator = new EdgeBookmarksMigrator();
   if (!bookmarksMigrator.exists) {
diff --git a/browser/components/migration/tests/unit/test_Edge_db_migration.js b/browser/components/migration/tests/unit/test_Edge_db_migration.js
new file mode 100644
index 000000000000..9da368c6c733
--- /dev/null
+++ b/browser/components/migration/tests/unit/test_Edge_db_migration.js
@@ -0,0 +1,465 @@
+"use strict";
+
+Cu.import("resource://gre/modules/ctypes.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+let eseBackStage = Cu.import("resource:///modules/ESEDBReader.jsm");
+let ESE = eseBackStage.ESE;
+let KERNEL = eseBackStage.KERNEL;
+let gLibs = eseBackStage.gLibs;
+let COLUMN_TYPES = eseBackStage.COLUMN_TYPES;
+let declareESEFunction = eseBackStage.declareESEFunction;
+let loadLibraries = eseBackStage.loadLibraries;
+
+let gESEInstanceCounter = 1;
+
+ESE.JET_COLUMNCREATE_W = new ctypes.StructType("JET_COLUMNCREATE_W", [
+  {"cbStruct": ctypes.unsigned_long},
+  {"szColumnName": ESE.JET_PCWSTR},
+  {"coltyp": ESE.JET_COLTYP },
+  {"cbMax": ctypes.unsigned_long },
+  {"grbit": ESE.JET_GRBIT },
+  {"pvDefault": ctypes.voidptr_t},
+  {"cbDefault": ctypes.unsigned_long },
+  {"cp": ctypes.unsigned_long },
+  {"columnid": ESE.JET_COLUMNID},
+  {"err": ESE.JET_ERR},
+]);
+
+function createColumnCreationWrapper({name, type, cbMax}) {
+  // We use a wrapper object because we need to be sure the JS engine won't GC
+  // data that we're "only" pointing to.
+  let wrapper = {};
+  wrapper.column = new ESE.JET_COLUMNCREATE_W();
+  wrapper.column.cbStruct = ESE.JET_COLUMNCREATE_W.size;
+  let wchar_tArray = ctypes.ArrayType(ctypes.char16_t);
+  wrapper.name = new wchar_tArray(name.length + 1);
+  wrapper.name.value = String(name);
+  wrapper.column.szColumnName = wrapper.name;
+  wrapper.column.coltyp = type;
+  let fallback = 0;
+  switch (type) {
+    case COLUMN_TYPES.JET_coltypText:
+      fallback = 255;
+    case COLUMN_TYPES.JET_coltypLongText:
+      wrapper.column.cbMax = cbMax || fallback || 64 * 1024;
+      break;
+    case COLUMN_TYPES.JET_coltypGUID:
+      wrapper.column.cbMax = 16;
+      break;
+    case COLUMN_TYPES.JET_coltypBit:
+      wrapper.column.cbMax = 1;
+      break;
+    case COLUMN_TYPES.JET_coltypLongLong:
+      wrapper.column.cbMax = 8;
+      break;
+    default:
+      throw "Unknown column type!";
+  }
+
+  wrapper.column.columnid = new ESE.JET_COLUMNID();
+  wrapper.column.grbit = 0;
+  wrapper.column.pvDefault = null;
+  wrapper.column.cbDefault = 0;
+  wrapper.column.cp = 0;
+
+  return wrapper;
+}
+
+// "forward declarations" of indexcreate and setinfo structs, which we don't use.
+ESE.JET_INDEXCREATE = new ctypes.StructType("JET_INDEXCREATE");
+ESE.JET_SETINFO = new ctypes.StructType("JET_SETINFO");
+
+ESE.JET_TABLECREATE_W = new ctypes.StructType("JET_TABLECREATE_W", [
+  {"cbStruct": ctypes.unsigned_long},
+  {"szTableName": ESE.JET_PCWSTR},
+  {"szTemplateTableName": ESE.JET_PCWSTR},
+  {"ulPages": ctypes.unsigned_long},
+  {"ulDensity": ctypes.unsigned_long},
+  {"rgcolumncreate": ESE.JET_COLUMNCREATE_W.ptr},
+  {"cColumns": ctypes.unsigned_long},
+  {"rgindexcreate": ESE.JET_INDEXCREATE.ptr},
+  {"cIndexes": ctypes.unsigned_long},
+  {"grbit": ESE.JET_GRBIT},
+  {"tableid": ESE.JET_TABLEID},
+  {"cCreated": ctypes.unsigned_long},
+]);
+
+function createTableCreationWrapper(tableName, columns) {
+  let wrapper = {};
+  let wchar_tArray = ctypes.ArrayType(ctypes.char16_t);
+  wrapper.name = new wchar_tArray(tableName.length + 1);
+  wrapper.name.value = String(tableName);
+  wrapper.table = new ESE.JET_TABLECREATE_W();
+  wrapper.table.cbStruct = ESE.JET_TABLECREATE_W.size;
+  wrapper.table.szTableName = wrapper.name;
+  wrapper.table.szTemplateTableName = null;
+  wrapper.table.ulPages = 1;
+  wrapper.table.ulDensity = 0;
+  let columnArrayType = ESE.JET_COLUMNCREATE_W.array(columns.length);
+  wrapper.columnAry = new columnArrayType();
+  wrapper.table.rgcolumncreate = wrapper.columnAry.addressOfElement(0);
+  wrapper.table.cColumns = columns.length;
+  wrapper.columns = [];
+  for (let i = 0; i < columns.length; i++) {
+    let column = columns[i];
+    let columnWrapper = createColumnCreationWrapper(column);
+    wrapper.columnAry.addressOfElement(i).contents = columnWrapper.column;
+    wrapper.columns.push(columnWrapper);
+  }
+  wrapper.table.rgindexcreate = null;
+  wrapper.table.cIndexes = 0;
+  return wrapper;
+}
+
+function convertValueForWriting(value, valueType) {
+  let buffer;
+  let valueOfValueType = ctypes.UInt64.lo(valueType);
+  switch (valueOfValueType) {
+    case COLUMN_TYPES.JET_coltypLongLong:
+      if (value instanceof Date) {
+        buffer = new KERNEL.FILETIME();
+        let sysTime = new KERNEL.SYSTEMTIME();
+        sysTime.wYear = value.getUTCFullYear();
+        sysTime.wMonth = value.getUTCMonth() + 1;
+        sysTime.wDay = value.getUTCDate();
+        sysTime.wHour = value.getUTCHours();
+        sysTime.wMinute = value.getUTCMinutes();
+        sysTime.wSecond = value.getUTCSeconds();
+        sysTime.wMilliseconds = value.getUTCMilliseconds();
+        let rv = KERNEL.SystemTimeToFileTime(sysTime.address(), buffer.address());
+        if (!rv) {
+          throw new Error("Failed to get FileTime.");
+        }
+        return [buffer, KERNEL.FILETIME.size];
+      }
+      throw new Error("Unrecognized value for longlong column");
+    case COLUMN_TYPES.JET_coltypLongText:
+      let wchar_tArray = ctypes.ArrayType(ctypes.char16_t);
+      buffer = new wchar_tArray(value.length + 1);
+      buffer.value = String(value);
+      return [buffer, buffer.length * 2];
+    case COLUMN_TYPES.JET_coltypBit:
+      buffer = new ctypes.uint8_t();
+      // Bizarre boolean values, but whatever:
+      buffer.value = value ? 255 : 0;
+      return [buffer, 1];
+    case COLUMN_TYPES.JET_coltypGUID:
+      let byteArray = ctypes.ArrayType(ctypes.uint8_t);
+      buffer = new byteArray(16);
+      let j = 0;
+      for (let i = 0; i < value.length; i++) {
+        if (!(/[0-9a-f]/i).test(value[i])) {
+          continue;
+        }
+        let byteAsHex = value.substr(i, 2);
+        buffer[j++] = parseInt(byteAsHex, 16);
+        i++;
+      }
+      return [buffer, 16];
+  }
+
+  throw new Error("Unknown type " + valueType);
+}
+
+let initializedESE = false;
+
+let eseDBWritingHelpers = {
+  setupDB(dbFile, tableName, columns, rows) {
+    if (!initializedESE) {
+      initializedESE = true;
+      loadLibraries();
+
+      KERNEL.SystemTimeToFileTime = gLibs.kernel.declare("SystemTimeToFileTime",
+          ctypes.default_abi, ctypes.bool, KERNEL.SYSTEMTIME.ptr, KERNEL.FILETIME.ptr);
+
+      declareESEFunction("CreateDatabaseW", ESE.JET_SESID, ESE.JET_PCWSTR,
+                         ESE.JET_PCWSTR, ESE.JET_DBID.ptr, ESE.JET_GRBIT);
+      declareESEFunction("CreateTableColumnIndexW", ESE.JET_SESID, ESE.JET_DBID,
+                         ESE.JET_TABLECREATE_W.ptr);
+      declareESEFunction("BeginTransaction", ESE.JET_SESID);
+      declareESEFunction("CommitTransaction", ESE.JET_SESID, ESE.JET_GRBIT);
+      declareESEFunction("PrepareUpdate", ESE.JET_SESID, ESE.JET_TABLEID,
+                         ctypes.unsigned_long);
+      declareESEFunction("Update", ESE.JET_SESID, ESE.JET_TABLEID,
+                         ctypes.voidptr_t, ctypes.unsigned_long,
+                         ctypes.unsigned_long.ptr);
+      declareESEFunction("SetColumn", ESE.JET_SESID, ESE.JET_TABLEID,
+                         ESE.JET_COLUMNID, ctypes.voidptr_t,
+                         ctypes.unsigned_long, ESE.JET_GRBIT, ESE.JET_SETINFO.ptr);
+      ESE.SetSystemParameterW(null, 0, 64 /* JET_paramDatabasePageSize*/,
+                              8192, null);
+    }
+
+    let rootPath = dbFile.parent.path + "\\";
+    let logPath = rootPath + "LogFiles\\";
+
+    try {
+      this._instanceId = new ESE.JET_INSTANCE();
+      ESE.CreateInstanceW(this._instanceId.address(),
+                          "firefox-dbwriter-" + (gESEInstanceCounter++));
+      this._instanceCreated = true;
+
+      ESE.SetSystemParameterW(this._instanceId.address(), 0,
+                              0 /* JET_paramSystemPath*/, 0, rootPath);
+      ESE.SetSystemParameterW(this._instanceId.address(), 0,
+                              1 /* JET_paramTempPath */, 0, rootPath);
+      ESE.SetSystemParameterW(this._instanceId.address(), 0,
+                              2 /* JET_paramLogFilePath*/, 0, logPath);
+      // Shouldn't try to call JetTerm if the following call fails.
+      this._instanceCreated = false;
+      ESE.Init(this._instanceId.address());
+      this._instanceCreated = true;
+      this._sessionId = new ESE.JET_SESID();
+      ESE.BeginSessionW(this._instanceId, this._sessionId.address(), null,
+                        null);
+      this._sessionCreated = true;
+
+      this._dbId = new ESE.JET_DBID();
+      this._dbPath = rootPath + "spartan.edb";
+      ESE.CreateDatabaseW(this._sessionId, this._dbPath, null,
+                          this._dbId.address(), 0);
+      this._opened = this._attached = true;
+
+      let tableCreationWrapper = createTableCreationWrapper(tableName, columns);
+      ESE.CreateTableColumnIndexW(this._sessionId, this._dbId,
+                                  tableCreationWrapper.table.address());
+      this._tableId = tableCreationWrapper.table.tableid;
+
+      let columnIdMap = new Map();
+      if (rows.length) {
+        // Iterate over the struct we passed into ESENT because they have the
+        // created column ids.
+        let columnCount = ctypes.UInt64.lo(tableCreationWrapper.table.cColumns);
+        let columnsPassed = tableCreationWrapper.table.rgcolumncreate;
+        for (let i = 0; i < columnCount; i++) {
+          let column = columnsPassed.contents;
+          columnIdMap.set(column.szColumnName.readString(), column);
+          columnsPassed = columnsPassed.increment();
+        }
+        let rv = ESE.ManualMove(this._sessionId, this._tableId,
+                                -2147483648 /* JET_MoveFirst */, 0);
+        ESE.BeginTransaction(this._sessionId);
+        for (let row of rows) {
+          ESE.PrepareUpdate(this._sessionId, this._tableId, 0 /* JET_prepInsert */);
+          for (let columnName in row) {
+            let col = columnIdMap.get(columnName);
+            let colId = col.columnid;
+            let [val, valSize] = convertValueForWriting(row[columnName], col.coltyp);
+            /* JET_bitSetOverwriteLV */
+            ESE.SetColumn(this._sessionId, this._tableId, colId, val.address(), valSize, 4, null);
+          }
+          let actualBookmarkSize = new ctypes.unsigned_long();
+          ESE.Update(this._sessionId, this._tableId, null, 0, actualBookmarkSize.address());
+        }
+        ESE.CommitTransaction(this._sessionId, 0 /* JET_bitWaitLastLevel0Commit */);
+      }
+    } finally {
+      try {
+        this._close();
+      } catch (ex) {
+        Cu.reportError(ex);
+      }
+    }
+
+  },
+
+  _close() {
+    if (this._tableId) {
+      ESE.FailSafeCloseTable(this._sessionId, this._tableId);
+      delete this._tableId;
+    }
+    if (this._opened) {
+      ESE.FailSafeCloseDatabase(this._sessionId, this._dbId, 0);
+      this._opened = false;
+    }
+    if (this._attached) {
+      ESE.FailSafeDetachDatabaseW(this._sessionId, this._dbPath);
+      this._attached = false;
+    }
+    if (this._sessionCreated) {
+      ESE.FailSafeEndSession(this._sessionId, 0);
+      this._sessionCreated = false;
+    }
+    if (this._instanceCreated) {
+      ESE.FailSafeTerm(this._instanceId);
+      this._instanceCreated = false;
+    }
+  },
+};
+
+add_task(function*() {
+  let tempFile = Services.dirsvc.get("TmpD", Ci.nsIFile);
+  tempFile.append("fx-xpcshell-edge-db");
+  tempFile.createUnique(tempFile.DIRECTORY_TYPE, 0o600);
+
+  let db = tempFile.clone();
+  db.append("spartan.edb");
+
+  let logs = tempFile.clone();
+  logs.append("LogFiles");
+  logs.create(tempFile.DIRECTORY_TYPE, 0o600);
+
+  let creationDate = new Date(Date.now() - 5000);
+  const kEdgeMenuParent = "62d07e2b-5f0d-4e41-8426-5f5ec9717beb";
+  let itemsInDB = [
+    {
+      URL: "http://www.mozilla.org/",
+      Title: "Mozilla",
+      DateUpdated: new Date(creationDate.valueOf() + 100),
+      ItemId: "1c00c10a-15f6-4618-92dd-22575102a4da",
+      ParentId: kEdgeMenuParent,
+      IsFolder: false,
+      IsDeleted: false,
+    },
+    {
+      Title: "Folder",
+      DateUpdated: new Date(creationDate.valueOf() + 200),
+      ItemId: "564b21f2-05d6-4f7d-8499-304d00ccc3aa",
+      ParentId: kEdgeMenuParent,
+      IsFolder: true,
+      IsDeleted: false,
+    },
+    {
+      Title: "Item in folder",
+      URL: "http://www.iteminfolder.org/",
+      DateUpdated: new Date(creationDate.valueOf() + 300),
+      ItemId: "c295ddaf-04a1-424a-866c-0ebde011e7c8",
+      ParentId: "564b21f2-05d6-4f7d-8499-304d00ccc3aa",
+      IsFolder: false,
+      IsDeleted: false,
+    },
+    {
+      Title: "Deleted folder",
+      DateUpdated: new Date(creationDate.valueOf() + 400),
+      ItemId: "a547573c-4d4d-4406-a736-5b5462d93bca",
+      ParentId: kEdgeMenuParent,
+      IsFolder: true,
+      IsDeleted: true,
+    },
+    {
+      Title: "Deleted item",
+      URL: "http://www.deleteditem.org/",
+      DateUpdated: new Date(creationDate.valueOf() + 500),
+      ItemId: "37a574bb-b44b-4bbc-a414-908615536435",
+      ParentId: kEdgeMenuParent,
+      IsFolder: false,
+      IsDeleted: true,
+    },
+    {
+      Title: "Item in deleted folder (should be in root)",
+      URL: "http://www.itemindeletedfolder.org/",
+      DateUpdated: new Date(creationDate.valueOf() + 600),
+      ItemId: "74dd1cc3-4c5d-471f-bccc-7bc7c72fa621",
+      ParentId: "a547573c-4d4d-4406-a736-5b5462d93bca",
+      IsFolder: false,
+      IsDeleted: false,
+    },
+    {
+      Title: "_Favorites_Bar_",
+      DateUpdated: new Date(creationDate.valueOf() + 700),
+      ItemId: "921dc8a0-6c83-40ef-8df1-9bd1c5c56aaf",
+      ParentId: kEdgeMenuParent,
+      IsFolder: true,
+      IsDeleted: false,
+    },
+    {
+      Title: "Item in favorites bar",
+      URL: "http://www.iteminfavoritesbar.org/",
+      DateUpdated: new Date(creationDate.valueOf() + 800),
+      ItemId: "9f2b1ff8-b651-46cf-8f41-16da8bcb6791",
+      ParentId: "921dc8a0-6c83-40ef-8df1-9bd1c5c56aaf",
+      IsFolder: false,
+      IsDeleted: false,
+    },
+  ];
+  eseDBWritingHelpers.setupDB(db, "Favorites", [
+    {type: COLUMN_TYPES.JET_coltypLongText, name: "URL", cbMax: 4096},
+    {type: COLUMN_TYPES.JET_coltypLongText, name: "Title", cbMax: 4096},
+    {type: COLUMN_TYPES.JET_coltypLongLong, name: "DateUpdated"},
+    {type: COLUMN_TYPES.JET_coltypGUID, name: "ItemId"},
+    {type: COLUMN_TYPES.JET_coltypBit, name: "IsDeleted"},
+    {type: COLUMN_TYPES.JET_coltypBit, name: "IsFolder"},
+    {type: COLUMN_TYPES.JET_coltypGUID, name: "ParentId"},
+  ], itemsInDB);
+
+  let migrator = Cc["@mozilla.org/profile/migrator;1?app=browser&type=edge"]
+                 .createInstance(Ci.nsIBrowserProfileMigrator);
+  let bookmarksMigrator = migrator.wrappedJSObject.getESEMigratorForTesting(db);
+  Assert.ok(bookmarksMigrator.exists, "Should recognize table we just created");
+
+  let seenBookmarks = [];
+  let bookmarkObserver = {
+    onItemAdded(itemId, parentId, index, itemType, url, title, dateAdded, itemGuid, parentGuid) {
+      if (title.startsWith("Deleted")) {
+        ok(false, "Should not see deleted items being bookmarked!");
+      }
+      seenBookmarks.push({itemId, parentId, index, itemType, url, title, dateAdded, itemGuid, parentGuid});
+    },
+    onBeginUpdateBatch() {},
+    onEndUpdateBatch() {},
+    onItemRemoved() {},
+    onItemChanged() {},
+    onItemVisited() {},
+    onItemMoved() {},
+  }
+  PlacesUtils.bookmarks.addObserver(bookmarkObserver, false);
+
+  let migrateResult = yield new Promise(resolve => bookmarksMigrator.migrate(resolve)).catch(ex => {
+    Cu.reportError(ex);
+    Assert.ok(false, "Got an exception trying to migrate data! " + ex);
+    return false;
+  });
+  PlacesUtils.bookmarks.removeObserver(bookmarkObserver);
+  Assert.ok(migrateResult, "Migration should succeed");
+  Assert.equal(seenBookmarks.length, 7, "Should have seen 7 items being bookmarked.");
+
+  let menuParents = seenBookmarks.filter(item => item.parentGuid == PlacesUtils.bookmarks.menuGuid);
+  Assert.equal(menuParents.length, 1, "Should have a single folder added to the menu");
+  let toolbarParents = seenBookmarks.filter(item => item.parentGuid == PlacesUtils.bookmarks.toolbarGuid);
+  Assert.equal(toolbarParents.length, 1, "Should have a single item added to the toolbar");
+  let menuParentGuid = menuParents[0].itemGuid;
+  let toolbarParentGuid = toolbarParents[0].itemGuid;
+
+  let expectedTitlesInMenu = itemsInDB.filter(item => item.ParentId == kEdgeMenuParent).map(item => item.Title);
+  // Hacky, but seems like much the simplest way:
+  expectedTitlesInMenu.push("Item in deleted folder (should be in root)");
+  let expectedTitlesInToolbar = itemsInDB.filter(item => item.ParentId == "921dc8a0-6c83-40ef-8df1-9bd1c5c56aaf").map(item => item.Title);
+
+  let edgeNameStr = MigrationUtils.getLocalizedString("sourceNameEdge");
+  let importParentFolderName = MigrationUtils.getLocalizedString("importedBookmarksFolder", [edgeNameStr]);
+
+  for (let bookmark of seenBookmarks) {
+    let shouldBeInMenu = expectedTitlesInMenu.includes(bookmark.title);
+    let shouldBeInToolbar = expectedTitlesInToolbar.includes(bookmark.title);
+    if (bookmark.title == "Folder" || bookmark.title == importParentFolderName) {
+      Assert.equal(bookmark.itemType, PlacesUtils.bookmarks.TYPE_FOLDER,
+          "Bookmark " + bookmark.title + " should be a folder");
+    } else {
+      Assert.notEqual(bookmark.itemType, PlacesUtils.bookmarks.TYPE_FOLDER,
+          "Bookmark " + bookmark.title + " should not be a folder");
+    }
+
+    if (shouldBeInMenu) {
+      Assert.equal(bookmark.parentGuid, menuParentGuid, "Item '" + bookmark.title + "' should be in menu");
+    } else if (shouldBeInToolbar) {
+      Assert.equal(bookmark.parentGuid, toolbarParentGuid, "Item '" + bookmark.title + "' should be in toolbar");
+    } else if (bookmark.itemGuid == menuParentGuid || bookmark.itemGuid == toolbarParentGuid) {
+      Assert.ok(true, "Expect toolbar and menu folders to not be in menu or toolbar");
+    } else {
+      // Bit hacky, but we do need to check this.
+      Assert.equal(bookmark.title, "Item in folder", "Subfoldered item shouldn't be in menu or toolbar");
+      let parent = seenBookmarks.find(maybeParent => maybeParent.itemGuid == bookmark.parentGuid);
+      Assert.equal(parent && parent.title, "Folder", "Subfoldered item should be in subfolder labeled 'Folder'");
+    }
+
+    let dbItem = itemsInDB.find(dbItem => bookmark.title == dbItem.Title);
+    if (!dbItem) {
+      Assert.equal(bookmark.title, importParentFolderName, "Only the extra layer of folders isn't in the input we stuck in the DB.");
+      Assert.ok([menuParentGuid, toolbarParentGuid].includes(bookmark.itemGuid), "This item should be one of the containers");
+    } else {
+      Assert.equal(dbItem.URL || null, bookmark.url && bookmark.url.spec, "URL is correct");
+      Assert.equal(dbItem.DateUpdated.valueOf(), (new Date(bookmark.dateAdded / 1000)).valueOf(), "Date added is correct");
+    }
+  }
+});
+
diff --git a/browser/components/migration/tests/unit/xpcshell.ini b/browser/components/migration/tests/unit/xpcshell.ini
index 050310fd39aa..a75dd2be5171 100644
--- a/browser/components/migration/tests/unit/xpcshell.ini
+++ b/browser/components/migration/tests/unit/xpcshell.ini
@@ -12,6 +12,8 @@ skip-if = os != "mac" # Relies on ULibDir
 [test_Chrome_passwords.js]
 skip-if = os != "win"
 [test_Edge_availability.js]
+[test_Edge_db_migration.js]
+skip-if = os != "win" || os_version == "5.1" || os_version == "5.2" # Relies on post-XP bits of ESEDB
 [test_fx_telemetry.js]
 [test_IE_bookmarks.js]
 skip-if = os != "win"
diff --git a/browser/components/preferences/in-content/sync.js b/browser/components/preferences/in-content/sync.js
index 0fab01450b4b..7c59cb3bf0f7 100644
--- a/browser/components/preferences/in-content/sync.js
+++ b/browser/components/preferences/in-content/sync.js
@@ -271,9 +271,7 @@ var gSyncPane = {
       gSyncPane.signIn();
       return false;
     });
-    setEventListener("verifiedManage", "click",
-      gSyncPane.manageFirefoxAccount);
-    setEventListener("fxaUnlinkButton", "click", function () {
+    setEventListener("fxaUnlinkButton", "command", function () {
       gSyncPane.unlinkFirefoxAccount(true);
     });
     setEventListener("verifyFxaAccount", "command",
@@ -550,13 +548,34 @@ var gSyncPane = {
     this._openAboutAccounts("reauth");
   },
 
-  openChangeProfileImage: function() {
-    fxAccounts.promiseAccountsChangeProfileURI(this._getEntryPoint(), "avatar")
-      .then(url => {
+
+  clickOrSpaceOrEnterPressed: function(event) {
+    // Note: charCode is deprecated, but 'char' not yet implemented.
+    // Replace charCode with char when implemented, see Bug 680830
+    if ((event.type == "click" && event.button == 0) ||    // button 0 = 'main button', typically left click.
+        (event.type == "keypress" &&
+        (event.charCode == KeyEvent.DOM_VK_SPACE || event.keyCode == KeyEvent.DOM_VK_RETURN))) {
+      return true;
+    } else {
+      return false;
+    }
+  },
+
+  openChangeProfileImage: function(event) {
+    if (this.clickOrSpaceOrEnterPressed(event)) {
+      fxAccounts.promiseAccountsChangeProfileURI(this._getEntryPoint(), "avatar")
+          .then(url => {
         this.openContentInBrowser(url, {
           replaceQueryString: true
         });
       });
+    }
+  },
+
+  openManageFirefoxAccount: function(event) {
+    if (this.clickOrSpaceOrEnterPressed(event)) {
+      this.manageFirefoxAccount();
+    }
   },
 
   manageFirefoxAccount: function() {
diff --git a/browser/components/preferences/in-content/sync.xul b/browser/components/preferences/in-content/sync.xul
index 4101cab87834..b54ddee5e021 100644
--- a/browser/components/preferences/in-content/sync.xul
+++ b/browser/components/preferences/in-content/sync.xul
@@ -199,8 +199,8 @@
               <vbox flex="1">
                 <label id="signedOutAccountBoxTitle">&signedOut.accountBox.title;</label>
                 <hbox class="fxaAccountBoxButtons" align="center">
-                  <button id="noFxaSignUp">&signedOut.accountBox.create;</button>
-                  <button id="noFxaSignIn">&signedOut.accountBox.signin;</button>
+                  <button id="noFxaSignUp" label="&signedOut.accountBox.create;"></button>
+                  <button id="noFxaSignIn" label="&signedOut.accountBox.signin;"></button>
                 </hbox>
               </vbox>
             </hbox>
@@ -234,16 +234,21 @@
             <!-- logged in and verified and all is good -->
             <hbox id="fxaLoginVerified" class="fxaAccountBox">
               <vbox>
-                <image id="fxaProfileImage"
-                    onclick="gSyncPane.openChangeProfileImage();" hidden="true"
-                    tooltiptext="&profilePicture.tooltip;" class="actionable"/>
+                <image id="fxaProfileImage" class="actionable"
+                    role="button"
+                    onclick="gSyncPane.openChangeProfileImage(event);" hidden="true"
+                    onkeypress="gSyncPane.openChangeProfileImage(event);"
+                    tooltiptext="&profilePicture.tooltip;"/>
               </vbox>
               <vbox flex="1">
                 <label id="fxaEmailAddress1"/>
                 <label id="fxaDisplayName" hidden="true"/>
                 <hbox class="fxaAccountBoxButtons" align="center">
-                  <button id="fxaUnlinkButton">&disconnect.label;</button>
-                  <label id="verifiedManage" class="text-link">&verifiedManage.label;</label>
+                  <button id="fxaUnlinkButton" label="&disconnect.label;"/>
+                  <label id="verifiedManage" class="text-link"
+                         onclick="gSyncPane.openManageFirefoxAccount(event);"
+                         onkeypress="gSyncPane.openManageFirefoxAccount(event);"><!--
+                  -->&verifiedManage.label;</label>
                 </hbox>
               </vbox>
             </hbox>
diff --git a/browser/components/sessionstore/SessionHistory.jsm b/browser/components/sessionstore/SessionHistory.jsm
index eaf0f5d68688..d3d31936e3a4 100644
--- a/browser/components/sessionstore/SessionHistory.jsm
+++ b/browser/components/sessionstore/SessionHistory.jsm
@@ -141,6 +141,10 @@ var SessionHistoryInternal = {
       entry.referrerPolicy = shEntry.referrerPolicy;
     }
 
+    if (shEntry.originalURI) {
+      entry.originalURI = shEntry.originalURI.spec;
+    }
+
     if (shEntry.srcdocData)
       entry.srcdocData = shEntry.srcdocData;
 
@@ -309,6 +313,9 @@ var SessionHistoryInternal = {
       shEntry.referrerURI = Utils.makeURI(entry.referrer);
       shEntry.referrerPolicy = entry.referrerPolicy;
     }
+    if (entry.originalURI) {
+      shEntry.originalURI = Utils.makeURI(entry.originalURI);
+    }
     if (entry.isSrcdocEntry)
       shEntry.srcdocData = entry.srcdocData;
     if (entry.baseURI)
diff --git a/browser/components/shell/ShellService.jsm b/browser/components/shell/ShellService.jsm
index f935eac94a79..2fd05d3f4c8f 100644
--- a/browser/components/shell/ShellService.jsm
+++ b/browser/components/shell/ShellService.jsm
@@ -11,6 +11,8 @@ const { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 Cu.import("resource://gre/modules/AppConstants.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "WindowsRegistry",
+                                  "resource://gre/modules/WindowsRegistry.jsm");
 
 /**
  * Internal functionality to save and restore the docShell.allow* properties.
@@ -54,11 +56,30 @@ let ShellServiceInternal = {
       return false;
     }
 
-    return Services.prefs.getBoolPref("browser.shell.checkDefaultBrowser");
+    if (!Services.prefs.getBoolPref("browser.shell.checkDefaultBrowser")) {
+      return false;
+    }
+
+    if (AppConstants.platform == "win") {
+      let optOutValue = WindowsRegistry.readRegKey(Ci.nsIWindowsRegKey.ROOT_KEY_CURRENT_USER,
+                                                   "Software\\Mozilla\\Firefox",
+                                                   "DefaultBrowserOptOut");
+      WindowsRegistry.removeRegKey(Ci.nsIWindowsRegKey.ROOT_KEY_CURRENT_USER,
+                                   "Software\\Mozilla\\Firefox",
+                                   "DefaultBrowserOptOut");
+      if (optOutValue == "True") {
+        Services.prefs.setBoolPref("browser.shell.checkDefaultBrowser", false);
+        return false;
+      }
+    }
+
+    return true;
   },
+
   set shouldCheckDefaultBrowser(shouldCheck) {
     Services.prefs.setBoolPref("browser.shell.checkDefaultBrowser", !!shouldCheck);
   },
+
   isDefaultBrowser(startupCheck, forAllTypes) {
     // If this is the first browser window, maintain internal state that we've
     // checked this session (so that subsequent window opens don't show the
diff --git a/browser/components/syncedtabs/sidebar.xhtml b/browser/components/syncedtabs/sidebar.xhtml
index 5329b117c5f2..d382bcbf4ed9 100644
--- a/browser/components/syncedtabs/sidebar.xhtml
+++ b/browser/components/syncedtabs/sidebar.xhtml
@@ -20,6 +20,7 @@
     <link rel="stylesheet" type="text/css" media="all" href="chrome://browser/skin/syncedtabs/sidebar.css"/>
     <link rel="stylesheet" type="text/css" media="all" href="chrome://global/skin/"/>
     <link rel="stylesheet" type="text/css" media="all" href="chrome://global/skin/textbox.css"/>
+    <link rel="stylesheet" type="text/css" media="all" href="chrome://browser/content/browser.css"/>
     <title>&syncedTabs.sidebar.label;</title>
   </head>
 
diff --git a/browser/components/uitour/test/head.js b/browser/components/uitour/test/head.js
index dedd0f1f8b60..b48ee0caf713 100644
--- a/browser/components/uitour/test/head.js
+++ b/browser/components/uitour/test/head.js
@@ -147,13 +147,14 @@ function hideInfoPromise(...args) {
  */
 function showInfoPromise(target, title, text, icon, buttonsFunctionName, optionsFunctionName) {
   let popup = document.getElementById("UITourTooltip");
+  let shownPromise = promisePanelElementShown(window, popup);
   return ContentTask.spawn(gTestTab.linkedBrowser, [...arguments], args => {
     let contentWin = Components.utils.waiveXrays(content);
     let [target, title, text, icon, buttonsFunctionName, optionsFunctionName] = args;
     let buttons = buttonsFunctionName ? contentWin[buttonsFunctionName]() : null;
     let options = optionsFunctionName ? contentWin[optionsFunctionName]() : null;
     contentWin.Mozilla.UITour.showInfo(target, title, text, icon, buttons, options);
-  }).then(() => promisePanelElementShown(window, popup));
+  }).then(() => shownPromise);
 }
 
 function showHighlightPromise(...args) {
@@ -193,7 +194,7 @@ function promisePanelElementEvent(win, aPanel, aEvent) {
   return new Promise((resolve, reject) => {
     let timeoutId = win.setTimeout(() => {
       aPanel.removeEventListener(aEvent, onPanelEvent);
-      reject("Event did not happen within 5 seconds.");
+      reject(aEvent + " event did not happen within 5 seconds.");
     }, 5000);
 
     function onPanelEvent(e) {
diff --git a/browser/installer/windows/nsis/installer.nsi b/browser/installer/windows/nsis/installer.nsi
index 70c605b87e11..4be6bdfec385 100755
--- a/browser/installer/windows/nsis/installer.nsi
+++ b/browser/installer/windows/nsis/installer.nsi
@@ -605,6 +605,12 @@ Section "-InstallEndCleanup"
         GetFunctionAddress $0 SetAsDefaultAppUserHKCU
         UAC::ExecCodeSegment $0
       ${EndIf}
+    ${Else}
+      ${LogHeader} "Writing default-browser opt-out"
+      WriteRegStr HKCU "Software\Mozilla\Firefox" "DefaultBrowserOptOut" "True"
+      ${If} ${Errors}
+        ${LogHeader} "Error writing default-browser opt-out"
+      ${EndIf}
     ${EndIf}
   ${EndUnless}
 
diff --git a/browser/locales/en-US/chrome/browser/feeds/subscribe.properties b/browser/locales/en-US/chrome/browser/feeds/subscribe.properties
index 359a66504120..474ce7262d6c 100644
--- a/browser/locales/en-US/chrome/browser/feeds/subscribe.properties
+++ b/browser/locales/en-US/chrome/browser/feeds/subscribe.properties
@@ -49,3 +49,4 @@ feedSubscriptionVideoPodcast2=You can subscribe to this video podcast to receive
 # "Add %appName (%appDomain) as an application for %protocolType links?"
 addProtocolHandler=Add %S (%S) as an application for %S links?
 addProtocolHandlerAddButton=Add Application
+addProtocolHandlerAddButtonAccesskey=A
\ No newline at end of file
diff --git a/browser/modules/BrowserUITelemetry.jsm b/browser/modules/BrowserUITelemetry.jsm
index b6ad5739d2e8..c95d7675c078 100644
--- a/browser/modules/BrowserUITelemetry.jsm
+++ b/browser/modules/BrowserUITelemetry.jsm
@@ -134,6 +134,7 @@ XPCOMUtils.defineLazyGetter(this, "ALL_BUILTIN_ITEMS", function() {
     "BMB_unsortedBookmarksPopup",
     "BMB_bookmarksToolbarPopup",
     "search-go-button",
+    "soundplaying-icon",
   ]
   return DEFAULT_ITEMS.concat(PALETTE_ITEMS)
                       .concat(SPECIAL_CASES);
@@ -610,6 +611,10 @@ this.BrowserUITelemetry = {
     this._countEvent(["forget-button", timeId]);
   },
 
+  countTabMutingEvent: function(action, reason) {
+    this._countEvent(["tab-audio-control", action, reason || "no reason given"]);
+  },
+
   _logAwesomeBarSearchResult: function (url) {
     let spec = Services.search.parseSubmissionURL(url);
     if (spec.engine) {
diff --git a/browser/themes/linux/menuPanel.png b/browser/themes/linux/menuPanel.png
index f8c7f889d607..036e2a148600 100644
Binary files a/browser/themes/linux/menuPanel.png and b/browser/themes/linux/menuPanel.png differ
diff --git a/browser/themes/linux/menuPanel@2x.png b/browser/themes/linux/menuPanel@2x.png
index 28176a120df7..093bfea6463d 100644
Binary files a/browser/themes/linux/menuPanel@2x.png and b/browser/themes/linux/menuPanel@2x.png differ
diff --git a/browser/themes/linux/preferences/in-content/preferences.css b/browser/themes/linux/preferences/in-content/preferences.css
index 11f22340efda..d0dd0adbdaa7 100644
--- a/browser/themes/linux/preferences/in-content/preferences.css
+++ b/browser/themes/linux/preferences/in-content/preferences.css
@@ -25,6 +25,10 @@
   margin-top: 2px !important;
 }
 
+#fxaProfileImage {
+  -moz-user-focus: normal;
+}
+
 menulist.actionsMenu > .menulist-dropmarker {
   margin-top: 11px;
   margin-bottom: 11px;
diff --git a/browser/themes/osx/menuPanel-yosemite.png b/browser/themes/osx/menuPanel-yosemite.png
index 74e4ca860cac..7380f450593d 100644
Binary files a/browser/themes/osx/menuPanel-yosemite.png and b/browser/themes/osx/menuPanel-yosemite.png differ
diff --git a/browser/themes/osx/menuPanel-yosemite@2x.png b/browser/themes/osx/menuPanel-yosemite@2x.png
index 072f6030ffb0..0b88145d0018 100644
Binary files a/browser/themes/osx/menuPanel-yosemite@2x.png and b/browser/themes/osx/menuPanel-yosemite@2x.png differ
diff --git a/browser/themes/osx/menuPanel.png b/browser/themes/osx/menuPanel.png
index d7e74f3a1104..a50fdab82099 100644
Binary files a/browser/themes/osx/menuPanel.png and b/browser/themes/osx/menuPanel.png differ
diff --git a/browser/themes/osx/menuPanel@2x.png b/browser/themes/osx/menuPanel@2x.png
index bff0b13c4abb..486dd7a520e6 100644
Binary files a/browser/themes/osx/menuPanel@2x.png and b/browser/themes/osx/menuPanel@2x.png differ
diff --git a/browser/themes/osx/preferences/in-content/preferences.css b/browser/themes/osx/preferences/in-content/preferences.css
index 0ba5d47fb826..aeb4a920e6f9 100644
--- a/browser/themes/osx/preferences/in-content/preferences.css
+++ b/browser/themes/osx/preferences/in-content/preferences.css
@@ -19,6 +19,10 @@ prefpane .groupbox-title {
   -moz-padding-start: 3px;
 }
 
+#fxaProfileImage {
+  -moz-user-focus: normal;
+}
+
 textbox + button {
   -moz-margin-start: -4px;
 }
diff --git a/browser/themes/shared/menupanel.inc.css b/browser/themes/shared/menupanel.inc.css
index 51067f168f9f..bc6b84bedb4c 100644
--- a/browser/themes/shared/menupanel.inc.css
+++ b/browser/themes/shared/menupanel.inc.css
@@ -63,6 +63,10 @@
     -moz-image-region: rect(0px, 1024px, 32px, 992px);
   }
 
+  #sync-button[cui-areatype="menu-panel"][panel-multiview-anchor=true] {
+    -moz-image-region: rect(32px, 1024px, 64px, 992px);
+  }
+
   #feed-button[cui-areatype="menu-panel"],
   toolbarpaletteitem[place="palette"] > #feed-button {
     -moz-image-region: rect(0px, 416px, 32px, 384px);
@@ -263,6 +267,10 @@
     -moz-image-region: rect(0px, 2048px, 64px, 1984px);
   }
 
+  #sync-button[cui-areatype="menu-panel"][panel-multiview-anchor=true] {
+    -moz-image-region: rect(64px, 2048px, 128px, 1984px);
+  }
+
   #feed-button[cui-areatype="menu-panel"],
   toolbarpaletteitem[place="palette"] > #feed-button {
     -moz-image-region: rect(0px, 832px, 64px, 768px);
diff --git a/browser/themes/windows/menuPanel-aero.png b/browser/themes/windows/menuPanel-aero.png
index 9058f6691178..e59bace3affa 100644
Binary files a/browser/themes/windows/menuPanel-aero.png and b/browser/themes/windows/menuPanel-aero.png differ
diff --git a/browser/themes/windows/menuPanel-aero@2x.png b/browser/themes/windows/menuPanel-aero@2x.png
index 72f315c0f062..2b53d54d4e10 100644
Binary files a/browser/themes/windows/menuPanel-aero@2x.png and b/browser/themes/windows/menuPanel-aero@2x.png differ
diff --git a/browser/themes/windows/menuPanel.png b/browser/themes/windows/menuPanel.png
index cfc37702e935..8a7032ce592c 100644
Binary files a/browser/themes/windows/menuPanel.png and b/browser/themes/windows/menuPanel.png differ
diff --git a/browser/themes/windows/menuPanel@2x.png b/browser/themes/windows/menuPanel@2x.png
index bd15b916c2a0..995c68476592 100644
Binary files a/browser/themes/windows/menuPanel@2x.png and b/browser/themes/windows/menuPanel@2x.png differ
diff --git a/browser/themes/windows/preferences/in-content/preferences.css b/browser/themes/windows/preferences/in-content/preferences.css
index 6c7c4b9c8e4e..69316c7bdafc 100644
--- a/browser/themes/windows/preferences/in-content/preferences.css
+++ b/browser/themes/windows/preferences/in-content/preferences.css
@@ -51,6 +51,10 @@ filefield + button {
   padding-bottom: 0; /* override padding from normal preferences.css */
 }
 
+#fxaProfileImage {
+  -moz-user-focus: normal;
+}
+
 /**
  * Dialog
  */
diff --git a/configure.in b/configure.in
index 35e0865ed7d5..ccf05dd74c4c 100644
--- a/configure.in
+++ b/configure.in
@@ -8562,10 +8562,12 @@ AC_SUBST(MOZ_CHILD_PROCESS_BUNDLE)
 # "Profile" field, which controls profile location.
 # - MOZ_APP_ID: When set, used for application.ini's "ID" field, and
 # crash reporter server url.
-# - MOZ_APP_ANDROID_VERSION_CODE: On android, "android:versionCode" for
+# - MOZ_APP_ANDROID_VERSION_CODE: On Android, "android:versionCode" for
 # the main application is set to the value of this variable.  If not
 # set, it falls back to a Mozilla-specific value derived from the
 # build ID.
+# - MOZ_ANDROID_SHARED_ID: On Android, "android:sharedUserId" for all Android
+# - packages produced.
 # - MOZ_PROFILE_MIGRATOR: When set, enables profile migrator.
 
 if test -z "$MOZ_APP_NAME"; then
@@ -8584,6 +8586,14 @@ if test -z "$ANDROID_PACKAGE_NAME" ; then
    ANDROID_PACKAGE_NAME="org.mozilla.$MOZ_APP_NAME"
 fi
 
+# Mozilla released Firefox for Android {Release,Beta} and {Aurora,Nightly} to
+# the public with specific common shared IDs and we need to keep them
+# consistent forever.  The specific common values are set by per-channel
+# branding; all other channels use a generic sharedID, set below.
+if test -z "$MOZ_ANDROID_SHARED_ID" ; then
+   MOZ_ANDROID_SHARED_ID="${ANDROID_PACKAGE_NAME}.sharedID"
+fi
+
 # For extensions and langpacks, we require a max version that is compatible
 # across security releases. MOZ_APP_MAXVERSION is our method for doing that.
 # 24.0a1 and 24.0a2 aren't affected
@@ -8614,6 +8624,7 @@ AC_SUBST(MOZ_APP_VENDOR)
 AC_SUBST(MOZ_APP_PROFILE)
 AC_SUBST(MOZ_APP_ID)
 AC_SUBST(MOZ_APP_ANDROID_VERSION_CODE)
+AC_SUBST(MOZ_ANDROID_SHARED_ID)
 AC_SUBST(MAR_CHANNEL_ID)
 AC_SUBST(ACCEPTED_MAR_CHANNEL_IDS)
 AC_SUBST(MOZ_PROFILE_MIGRATOR)
diff --git a/devtools/client/aboutdebugging/aboutdebugging.css b/devtools/client/aboutdebugging/aboutdebugging.css
index 1857e3673db8..bd89af2c1f59 100644
--- a/devtools/client/aboutdebugging/aboutdebugging.css
+++ b/devtools/client/aboutdebugging/aboutdebugging.css
@@ -16,11 +16,6 @@ button {
   padding-right: 20px;
 }
 
-#body {
-  display: flex;
-  flex-direction: row;
-}
-
 /* Category tabs */
 
 .category {
@@ -33,6 +28,13 @@ button {
   cursor: default;
 }
 
+.app {
+  height: 100%;
+  width: 100%;
+  display: flex;
+  flex-direction: row;
+}
+
 .main-content {
   flex: 1;
 }
@@ -41,10 +43,6 @@ button {
   max-width: 800px;
 }
 
-.tab:not(.active) {
-  display: none;
-}
-
 /* Prefs */
 
 label {
@@ -82,11 +80,11 @@ label {
   flex: 1;
 }
 
-.addon-controls {
+.addons-controls {
   display: flex;
   flex-direction: row;
 }
 
-.addon-options {
+.addons-options {
   flex: 1;
 }
diff --git a/devtools/client/aboutdebugging/aboutdebugging.js b/devtools/client/aboutdebugging/aboutdebugging.js
deleted file mode 100644
index 55ddecb70d2d..000000000000
--- a/devtools/client/aboutdebugging/aboutdebugging.js
+++ /dev/null
@@ -1,179 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-/* eslint-env browser */
-/* global AddonsComponent, DebuggerClient, DebuggerServer, React,
-   WorkersComponent */
-
-"use strict";
-
-const { classes: Cc, interfaces: Ci } = Components;
-const { loader } = Components.utils.import(
-  "resource://devtools/shared/Loader.jsm", {});
-
-loader.lazyRequireGetter(this, "AddonsComponent",
-  "devtools/client/aboutdebugging/components/addons", true);
-loader.lazyRequireGetter(this, "DebuggerClient",
-  "devtools/shared/client/main", true);
-loader.lazyRequireGetter(this, "DebuggerServer",
-  "devtools/server/main", true);
-loader.lazyRequireGetter(this, "Telemetry",
-  "devtools/client/shared/telemetry");
-loader.lazyRequireGetter(this, "WorkersComponent",
-  "devtools/client/aboutdebugging/components/workers", true);
-loader.lazyRequireGetter(this, "Services");
-
-loader.lazyImporter(this, "AddonManager",
-  "resource://gre/modules/AddonManager.jsm");
-
-const Strings = Services.strings.createBundle(
-  "chrome://devtools/locale/aboutdebugging.properties");
-
-var AboutDebugging = {
-  _prefListeners: [],
-
-  // Pointer to the current React component.
-  _component: null,
-
-  _categories: null,
-  get categories() {
-    // If needed, initialize the list of available categories.
-    if (!this._categories) {
-      let elements = document.querySelectorAll(".category");
-      this._categories = Array.map(elements, element => {
-        let value = element.getAttribute("value");
-        element.addEventListener("click", this.showTab.bind(this, value));
-        return value;
-      });
-    }
-    return this._categories;
-  },
-
-  showTab(category) {
-    // If no category was specified, try the URL hash.
-    if (!category) {
-      category = location.hash.substr(1);
-    }
-    // If no corresponding category can be found, use the first available.
-    let categories = this.categories;
-    if (categories.indexOf(category) < 0) {
-      category = categories[0];
-    }
-    // Show the corresponding tab and hide the others.
-    document.querySelector(".tab.active").classList.remove("active");
-    document.querySelector("#tab-" + category).classList.add("active");
-    document.querySelector(".category[selected]").removeAttribute("selected");
-    document.querySelector(".category[value=" + category + "]")
-      .setAttribute("selected", "true");
-    location.hash = "#" + category;
-
-    if (category == "addons") {
-      this._component = React.render(React.createElement(AddonsComponent,
-        {client: this.client}), document.querySelector("#addons"));
-    } else if (category == "workers") {
-      this._component = React.render(React.createElement(WorkersComponent,
-        {client: this.client}), document.querySelector("#workers"));
-    }
-  },
-
-  init() {
-    let telemetry = this._telemetry = new Telemetry();
-    telemetry.toolOpened("aboutdebugging");
-
-    // Link checkboxes to prefs.
-    let elements = document.querySelectorAll("input[type=checkbox][data-pref]");
-    Array.map(elements, element => {
-      let pref = element.dataset.pref;
-
-      let updatePref = () => {
-        Services.prefs.setBoolPref(pref, element.checked);
-      };
-      element.addEventListener("change", updatePref, false);
-
-      let onPreferenceChanged = () => {
-        element.checked = Services.prefs.getBoolPref(pref);
-        this.update();
-      };
-
-      Services.prefs.addObserver(pref, onPreferenceChanged, false);
-      this._prefListeners.push([pref, onPreferenceChanged]);
-
-      // Initialize the current checkbox element.
-      element.checked = Services.prefs.getBoolPref(pref);
-    });
-
-    // Link buttons to their associated actions.
-    let loadAddonButton = document.getElementById("load-addon-from-file");
-    loadAddonButton.addEventListener("click", this.loadAddonFromFile);
-
-    if (!DebuggerServer.initialized) {
-      DebuggerServer.init();
-      DebuggerServer.addBrowserActors();
-    }
-    DebuggerServer.allowChromeProcess = true;
-    this.client = new DebuggerClient(DebuggerServer.connectPipe());
-
-    this.client.connect().then(() => {
-      // Show the first available tab.
-      this.showTab();
-      window.addEventListener("hashchange", () => this.showTab());
-    });
-  },
-
-  update() {
-    if (this._component) {
-      this._component.setState({});
-    }
-  },
-
-  loadAddonFromFile() {
-    let fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
-    fp.init(window,
-      Strings.GetStringFromName("selectAddonFromFile"),
-      Ci.nsIFilePicker.modeOpen);
-    let res = fp.show();
-    if (res == Ci.nsIFilePicker.returnCancel || !fp.file) {
-      return;
-    }
-    let file = fp.file;
-    // AddonManager.installTemporaryAddon accepts either
-    // addon directory or final xpi file.
-    if (!file.isDirectory() && !file.leafName.endsWith(".xpi")) {
-      file = file.parent;
-    }
-    try {
-      AddonManager.installTemporaryAddon(file);
-    } catch (e) {
-      alert("Error while installing the addon:\n" + e.message + "\n");
-      throw e;
-    }
-  },
-
-  destroy() {
-    let telemetry = this._telemetry;
-    telemetry.toolClosed("aboutdebugging");
-    telemetry.destroy();
-
-    this._prefListeners.forEach(([pref, listener]) => {
-      Services.prefs.removeObserver(pref, listener);
-    });
-    this._prefListeners = [];
-
-    React.unmountComponentAtNode(document.querySelector("#addons"));
-    React.unmountComponentAtNode(document.querySelector("#workers"));
-
-    this.client.close();
-    this.client = null;
-  },
-};
-
-window.addEventListener("DOMContentLoaded", function load() {
-  window.removeEventListener("DOMContentLoaded", load);
-  AboutDebugging.init();
-});
-
-window.addEventListener("unload", function unload() {
-  window.removeEventListener("unload", unload);
-  AboutDebugging.destroy();
-});
diff --git a/devtools/client/aboutdebugging/aboutdebugging.xhtml b/devtools/client/aboutdebugging/aboutdebugging.xhtml
index 342cbfde9adb..754f2c06c471 100644
--- a/devtools/client/aboutdebugging/aboutdebugging.xhtml
+++ b/devtools/client/aboutdebugging/aboutdebugging.xhtml
@@ -16,39 +16,8 @@
     <link rel="stylesheet" href="chrome://global/skin/in-content/common.css" type="text/css"/>
     <link rel="stylesheet" href="chrome://devtools/content/aboutdebugging/aboutdebugging.css"  type="text/css"/>
     <script type="application/javascript" src="resource://devtools/client/shared/vendor/react.js"></script>
-    <script type="application/javascript;version=1.8" src="chrome://devtools/content/aboutdebugging/aboutdebugging.js"></script>
+    <script type="application/javascript;version=1.8" src="chrome://devtools/content/aboutdebugging/initializer.js"></script>
   </head>
   <body id="body">
-    <div id="categories">
-      <div class="category" value="addons" selected="true">
-        <img class="category-icon" src="chrome://devtools/skin/images/debugging-addons.svg"/>
-        <div class="category-name">&aboutDebugging.addons;</div>
-      </div>
-      <div class="category" value="workers">
-        <img class="category-icon" src="chrome://devtools/skin/images/debugging-workers.svg"/>
-        <div class="category-name">&aboutDebugging.workers;</div>
-      </div>
-    </div>
-    <div class="main-content">
-      <div id="tab-addons" class="tab active">
-        <div class="header">
-          <h1 class="header-name">&aboutDebugging.addons;</h1>
-        </div>
-        <div class="addon-controls">
-          <div class="addon-options">
-            <input id="enable-addon-debugging" type="checkbox" data-pref="devtools.chrome.enabled"/>
-            <label for="enable-addon-debugging" title="&aboutDebugging.addonDebugging.tooltip;">&aboutDebugging.addonDebugging.label;</label>
-          </div>
-          <button id="load-addon-from-file">&aboutDebugging.loadTemporaryAddon;</button>
-        </div>
-        <div id="addons"></div>
-      </div>
-      <div id="tab-workers" class="tab">
-        <div class="header">
-          <h1 class="header-name">&aboutDebugging.workers;</h1>
-        </div>
-        <div id="workers"></div>
-      </div>
-    </div>
   </body>
 </html>
diff --git a/devtools/client/aboutdebugging/components/aboutdebugging.js b/devtools/client/aboutdebugging/components/aboutdebugging.js
new file mode 100644
index 000000000000..2b731bfffdbd
--- /dev/null
+++ b/devtools/client/aboutdebugging/components/aboutdebugging.js
@@ -0,0 +1,84 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* global React */
+
+"use strict";
+
+loader.lazyRequireGetter(this, "React",
+  "devtools/client/shared/vendor/react");
+loader.lazyRequireGetter(this, "AddonsTab",
+  "devtools/client/aboutdebugging/components/addons-tab", true);
+loader.lazyRequireGetter(this, "TabMenu",
+  "devtools/client/aboutdebugging/components/tab-menu", true);
+loader.lazyRequireGetter(this, "WorkersTab",
+  "devtools/client/aboutdebugging/components/workers-tab", true);
+
+const Strings = Services.strings.createBundle(
+  "chrome://devtools/locale/aboutdebugging.properties");
+
+const tabs = [
+  { id: "addons", name: Strings.GetStringFromName("addons"),
+    icon: "chrome://devtools/skin/images/debugging-addons.svg",
+    component: AddonsTab },
+  { id: "workers", name: Strings.GetStringFromName("workers"),
+    icon: "chrome://devtools/skin/images/debugging-workers.svg",
+    component: WorkersTab },
+];
+const defaultTabId = "addons";
+
+exports.AboutDebuggingApp = React.createClass({
+  displayName: "AboutDebuggingApp",
+
+  getInitialState() {
+    return {
+      selectedTabId: defaultTabId
+    };
+  },
+
+  componentDidMount() {
+    this.props.window.addEventListener("hashchange", this.onHashChange);
+    this.onHashChange();
+    this.props.telemetry.toolOpened("aboutdebugging");
+  },
+
+  componentWillUnmount() {
+    this.props.window.removeEventListener("hashchange", this.onHashChange);
+    this.props.telemetry.toolClosed("aboutdebugging");
+    this.props.telemetry.destroy();
+  },
+
+  render() {
+    let { client } = this.props;
+    let { selectedTabId } = this.state;
+    let selectTab = this.selectTab;
+
+    let selectedTab = tabs.find(t => t.id == selectedTabId);
+
+    return React.createElement(
+      "div", { className: "app"},
+        React.createElement(TabMenu, { tabs, selectedTabId, selectTab }),
+        React.createElement("div", { className: "main-content" },
+          React.createElement(selectedTab.component, { client }))
+        );
+  },
+
+  onHashChange() {
+    let tabId = this.props.window.location.hash.substr(1);
+
+    let isValid = tabs.some(t => t.id == tabId);
+    if (isValid) {
+      this.setState({ selectedTabId: tabId });
+    } else {
+      // If the current hash matches no valid category, navigate to the default
+      // tab.
+      this.selectTab(defaultTabId);
+    }
+  },
+
+  selectTab(tabId) {
+    let win = this.props.window;
+    win.location.hash = "#" + tabId;
+  }
+});
diff --git a/devtools/client/aboutdebugging/components/addons-controls.js b/devtools/client/aboutdebugging/components/addons-controls.js
new file mode 100644
index 000000000000..81964758e465
--- /dev/null
+++ b/devtools/client/aboutdebugging/components/addons-controls.js
@@ -0,0 +1,76 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* global React */
+
+"use strict";
+
+loader.lazyRequireGetter(this, "Ci", "chrome", true);
+loader.lazyRequireGetter(this, "Cc", "chrome", true);
+loader.lazyRequireGetter(this, "React", "devtools/client/shared/vendor/react");
+loader.lazyRequireGetter(this, "Services");
+
+loader.lazyImporter(this, "AddonManager",
+  "resource://gre/modules/AddonManager.jsm");
+
+const Strings = Services.strings.createBundle(
+  "chrome://devtools/locale/aboutdebugging.properties");
+
+exports.AddonsControls = React.createClass({
+  displayName: "AddonsControls",
+
+  render() {
+    let { debugDisabled } = this.props;
+
+    return React.createElement(
+      "div", { className: "addons-controls" }, React.createElement(
+        "div", { className: "addons-options" },
+          React.createElement("input", {
+            id: "enable-addon-debugging",
+            type: "checkbox",
+            checked: !debugDisabled,
+            onChange: this.onEnableAddonDebuggingChange,
+          }),
+          React.createElement("label", {
+            htmlFor: "enable-addon-debugging",
+            title: Strings.GetStringFromName("addonDebugging.tooltip")
+          }, Strings.GetStringFromName("addonDebugging.label"))
+        ),
+        React.createElement("button", {
+          id: "load-addon-from-file",
+          onClick: this.loadAddonFromFile,
+        }, Strings.GetStringFromName("loadTemporaryAddon"))
+      );
+  },
+
+  onEnableAddonDebuggingChange(event) {
+    let enabled = event.target.checked;
+    Services.prefs.setBoolPref("devtools.chrome.enabled", enabled);
+  },
+
+  loadAddonFromFile(event) {
+    let win = event.target.ownerDocument.defaultView;
+
+    let fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
+    fp.init(win,
+      Strings.GetStringFromName("selectAddonFromFile"),
+      Ci.nsIFilePicker.modeOpen);
+    let res = fp.show();
+    if (res == Ci.nsIFilePicker.returnCancel || !fp.file) {
+      return;
+    }
+    let file = fp.file;
+    // AddonManager.installTemporaryAddon accepts either
+    // addon directory or final xpi file.
+    if (!file.isDirectory() && !file.leafName.endsWith(".xpi")) {
+      file = file.parent;
+    }
+    try {
+      AddonManager.installTemporaryAddon(file);
+    } catch (e) {
+      win.alert("Error while installing the addon:\n" + e.message + "\n");
+      throw e;
+    }
+  },
+});
diff --git a/devtools/client/aboutdebugging/components/addons-tab.js b/devtools/client/aboutdebugging/components/addons-tab.js
new file mode 100644
index 000000000000..8a6cf677680b
--- /dev/null
+++ b/devtools/client/aboutdebugging/components/addons-tab.js
@@ -0,0 +1,117 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* global AddonManager, React */
+
+"use strict";
+
+loader.lazyRequireGetter(this, "React",
+  "devtools/client/shared/vendor/react");
+loader.lazyRequireGetter(this, "TargetList",
+  "devtools/client/aboutdebugging/components/target-list", true);
+loader.lazyRequireGetter(this, "TabHeader",
+  "devtools/client/aboutdebugging/components/tab-header", true);
+loader.lazyRequireGetter(this, "AddonsControls",
+  "devtools/client/aboutdebugging/components/addons-controls", true);
+loader.lazyRequireGetter(this, "Services");
+
+loader.lazyImporter(this, "AddonManager",
+  "resource://gre/modules/AddonManager.jsm");
+
+const ExtensionIcon = "chrome://mozapps/skin/extensions/extensionGeneric.svg";
+const Strings = Services.strings.createBundle(
+  "chrome://devtools/locale/aboutdebugging.properties");
+
+exports.AddonsTab = React.createClass({
+  displayName: "AddonsTab",
+
+  getInitialState() {
+    return {
+      extensions: [],
+      debugDisabled: false,
+    };
+  },
+
+  componentDidMount() {
+    AddonManager.addAddonListener(this);
+    Services.prefs.addObserver("devtools.chrome.enabled",
+      this.updateDebugStatus, false);
+    this.updateDebugStatus();
+    this.updateAddonsList();
+  },
+
+  componentWillUnmount() {
+    AddonManager.removeAddonListener(this);
+    Services.prefs.removeObserver("devtools.chrome.enabled",
+      this.updateDebugStatus);
+  },
+
+  render() {
+    let { client } = this.props;
+    let { debugDisabled, extensions: targets } = this.state;
+    let name = Strings.GetStringFromName("extensions");
+
+    return React.createElement(
+      "div", { id: "tab-addons", className: "tab", role: "tabpanel",
+        "aria-labelledby": "tab-addons-header-name" },
+        React.createElement(TabHeader, {
+          id: "tab-addons-header-name",
+          name: Strings.GetStringFromName("addons")}),
+        React.createElement(AddonsControls, { debugDisabled }),
+        React.createElement(
+          "div", { id: "addons" },
+          React.createElement(TargetList,
+            { name, targets, client, debugDisabled })
+      )
+    );
+  },
+
+  updateDebugStatus() {
+    this.setState({
+      debugDisabled: !Services.prefs.getBoolPref("devtools.chrome.enabled")
+    });
+  },
+
+  updateAddonsList() {
+    AddonManager.getAllAddons(addons => {
+      let extensions = addons.filter(addon => addon.isDebuggable).map(addon => {
+        return {
+          name: addon.name,
+          icon: addon.iconURL || ExtensionIcon,
+          type: addon.type,
+          addonID: addon.id
+        };
+      });
+      this.setState({ extensions });
+    });
+  },
+
+  /**
+   * Mandatory callback as AddonManager listener.
+   */
+  onInstalled() {
+    this.updateAddonsList();
+  },
+
+  /**
+   * Mandatory callback as AddonManager listener.
+   */
+  onUninstalled() {
+    this.updateAddonsList();
+  },
+
+  /**
+   * Mandatory callback as AddonManager listener.
+   */
+  onEnabled() {
+    this.updateAddonsList();
+  },
+
+  /**
+   * Mandatory callback as AddonManager listener.
+   */
+  onDisabled() {
+    this.updateAddonsList();
+  },
+});
diff --git a/devtools/client/aboutdebugging/components/addons.js b/devtools/client/aboutdebugging/components/addons.js
deleted file mode 100644
index edfb60fa0e49..000000000000
--- a/devtools/client/aboutdebugging/components/addons.js
+++ /dev/null
@@ -1,80 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-/* global AddonManager, React, TargetListComponent */
-
-"use strict";
-
-loader.lazyRequireGetter(this, "React",
-  "devtools/client/shared/vendor/react");
-loader.lazyRequireGetter(this, "TargetListComponent",
-  "devtools/client/aboutdebugging/components/target-list", true);
-loader.lazyRequireGetter(this, "Services");
-
-loader.lazyImporter(this, "AddonManager",
-  "resource://gre/modules/AddonManager.jsm");
-
-const ExtensionIcon = "chrome://mozapps/skin/extensions/extensionGeneric.svg";
-const Strings = Services.strings.createBundle(
-  "chrome://devtools/locale/aboutdebugging.properties");
-
-exports.AddonsComponent = React.createClass({
-  displayName: "AddonsComponent",
-
-  getInitialState() {
-    return {
-      extensions: []
-    };
-  },
-
-  componentDidMount() {
-    AddonManager.addAddonListener(this);
-    this.update();
-  },
-
-  componentWillUnmount() {
-    AddonManager.removeAddonListener(this);
-  },
-
-  render() {
-    let client = this.props.client;
-    let targets = this.state.extensions;
-    let name = Strings.GetStringFromName("extensions");
-    let debugDisabled = !Services.prefs.getBoolPref("devtools.chrome.enabled");
-    return React.createElement("div", null,
-      React.createElement(TargetListComponent,
-        { name, targets, client, debugDisabled })
-    );
-  },
-
-  update() {
-    AddonManager.getAllAddons(addons => {
-      let extensions = addons.filter(addon => addon.isDebuggable).map(addon => {
-        return {
-          name: addon.name,
-          icon: addon.iconURL || ExtensionIcon,
-          type: addon.type,
-          addonID: addon.id
-        };
-      });
-      this.setState({ extensions });
-    });
-  },
-
-  onInstalled() {
-    this.update();
-  },
-
-  onUninstalled() {
-    this.update();
-  },
-
-  onEnabled() {
-    this.update();
-  },
-
-  onDisabled() {
-    this.update();
-  },
-});
diff --git a/devtools/client/aboutdebugging/components/moz.build b/devtools/client/aboutdebugging/components/moz.build
index 17136732f3aa..1201ef6e2e50 100644
--- a/devtools/client/aboutdebugging/components/moz.build
+++ b/devtools/client/aboutdebugging/components/moz.build
@@ -3,8 +3,13 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 DevToolsModules(
-    'addons.js',
+    'aboutdebugging.js',
+    'addons-controls.js',
+    'addons-tab.js',
+    'tab-header.js',
+    'tab-menu-entry.js',
+    'tab-menu.js',
     'target-list.js',
     'target.js',
-    'workers.js',
+    'workers-tab.js',
 )
diff --git a/devtools/client/aboutdebugging/components/tab-header.js b/devtools/client/aboutdebugging/components/tab-header.js
new file mode 100644
index 000000000000..029786ccd6c8
--- /dev/null
+++ b/devtools/client/aboutdebugging/components/tab-header.js
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* global React */
+
+"use strict";
+
+loader.lazyRequireGetter(this, "React",
+  "devtools/client/shared/vendor/react");
+
+exports.TabHeader = React.createClass({
+  displayName: "TabHeader",
+
+  render() {
+    let { name, id } = this.props;
+
+    return React.createElement(
+      "div", { className: "header" }, React.createElement(
+        "h1", { id, className: "header-name" }, name));
+  },
+});
diff --git a/devtools/client/aboutdebugging/components/tab-menu-entry.js b/devtools/client/aboutdebugging/components/tab-menu-entry.js
new file mode 100644
index 000000000000..8412e4e38edf
--- /dev/null
+++ b/devtools/client/aboutdebugging/components/tab-menu-entry.js
@@ -0,0 +1,33 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* global React */
+
+"use strict";
+
+loader.lazyRequireGetter(this, "React",
+  "devtools/client/shared/vendor/react");
+
+exports.TabMenuEntry = React.createClass({
+  displayName: "TabMenuEntry",
+
+  render() {
+    let { icon, name, selected } = this.props;
+
+    // Here .category, .category-icon, .category-name classnames are used to
+    // apply common styles defined.
+    let className = "category" + (selected ? " selected" : "");
+    return React.createElement(
+      "div", { className, onClick: this.onClick,
+        "aria-selected": selected, role: "tab" },
+        React.createElement("img", { className: "category-icon", src: icon,
+          role: "presentation" }),
+        React.createElement("div", { className: "category-name" }, name)
+      );
+  },
+
+  onClick() {
+    this.props.selectTab(this.props.tabId);
+  }
+});
diff --git a/devtools/client/aboutdebugging/components/tab-menu.js b/devtools/client/aboutdebugging/components/tab-menu.js
new file mode 100644
index 000000000000..73a9ee42c1b8
--- /dev/null
+++ b/devtools/client/aboutdebugging/components/tab-menu.js
@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* global React */
+
+"use strict";
+
+loader.lazyRequireGetter(this, "React",
+  "devtools/client/shared/vendor/react");
+loader.lazyRequireGetter(this, "TabMenuEntry",
+  "devtools/client/aboutdebugging/components/tab-menu-entry", true);
+
+exports.TabMenu = React.createClass({
+  displayName: "TabMenu",
+
+  render() {
+    let { tabs, selectedTabId, selectTab } = this.props;
+    let tabLinks = tabs.map(({ id, name, icon }) => {
+      let selected = id == selectedTabId;
+      return React.createElement(TabMenuEntry,
+        { tabId: id, name, icon, selected, selectTab });
+    });
+
+    // "categories" id used for styling purposes
+    return React.createElement("div", { id: "categories" }, tabLinks);
+  },
+});
diff --git a/devtools/client/aboutdebugging/components/target-list.js b/devtools/client/aboutdebugging/components/target-list.js
index 6b51a0964ddf..a0af86f97651 100644
--- a/devtools/client/aboutdebugging/components/target-list.js
+++ b/devtools/client/aboutdebugging/components/target-list.js
@@ -2,13 +2,13 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-/* global React, TargetComponent */
+/* global React */
 
 "use strict";
 
 loader.lazyRequireGetter(this, "React",
   "devtools/client/shared/vendor/react");
-loader.lazyRequireGetter(this, "TargetComponent",
+loader.lazyRequireGetter(this, "Target",
   "devtools/client/aboutdebugging/components/target", true);
 loader.lazyRequireGetter(this, "Services");
 
@@ -18,15 +18,13 @@ const LocaleCompare = (a, b) => {
   return a.name.toLowerCase().localeCompare(b.name.toLowerCase());
 };
 
-exports.TargetListComponent = React.createClass({
-  displayName: "TargetListComponent",
+exports.TargetList = React.createClass({
+  displayName: "TargetList",
 
   render() {
-    let client = this.props.client;
-    let debugDisabled = this.props.debugDisabled;
+    let { client, debugDisabled } = this.props;
     let targets = this.props.targets.sort(LocaleCompare).map(target => {
-      return React.createElement(TargetComponent,
-        { client, target, debugDisabled });
+      return React.createElement(Target, { client, target, debugDisabled });
     });
     return (
       React.createElement("div", { id: this.props.id, className: "targets" },
diff --git a/devtools/client/aboutdebugging/components/target.js b/devtools/client/aboutdebugging/components/target.js
index 44e3bf2cb0ac..f96e1731104b 100644
--- a/devtools/client/aboutdebugging/components/target.js
+++ b/devtools/client/aboutdebugging/components/target.js
@@ -23,12 +23,11 @@ loader.lazyRequireGetter(this, "gDevTools",
 const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 
-exports.TargetComponent = React.createClass({
-  displayName: "TargetComponent",
+exports.Target = React.createClass({
+  displayName: "Target",
 
   debug() {
-    let client = this.props.client;
-    let target = this.props.target;
+    let { client, target } = this.props;
     switch (target.type) {
       case "extension":
         BrowserToolboxProcess.init({ addonID: target.addonID });
@@ -53,12 +52,11 @@ exports.TargetComponent = React.createClass({
   },
 
   render() {
-    let target = this.props.target;
-    let debugDisabled = this.props.debugDisabled;
-
+    let { target, debugDisabled } = this.props;
     return React.createElement("div", { className: "target" },
       React.createElement("img", {
         className: "target-icon",
+        role: "presentation",
         src: target.icon }),
       React.createElement("div", { className: "target-details" },
         React.createElement("div", { className: "target-name" }, target.name),
diff --git a/devtools/client/aboutdebugging/components/workers.js b/devtools/client/aboutdebugging/components/workers-tab.js
similarity index 68%
rename from devtools/client/aboutdebugging/components/workers.js
rename to devtools/client/aboutdebugging/components/workers-tab.js
index 87c4578e2991..59d96e218313 100644
--- a/devtools/client/aboutdebugging/components/workers.js
+++ b/devtools/client/aboutdebugging/components/workers-tab.js
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-/* global React, TargetListComponent */
+/* global React */
 
 "use strict";
 
@@ -10,8 +10,10 @@ loader.lazyRequireGetter(this, "Ci",
   "chrome", true);
 loader.lazyRequireGetter(this, "React",
   "devtools/client/shared/vendor/react");
-loader.lazyRequireGetter(this, "TargetListComponent",
+loader.lazyRequireGetter(this, "TargetList",
   "devtools/client/aboutdebugging/components/target-list", true);
+loader.lazyRequireGetter(this, "TabHeader",
+  "devtools/client/aboutdebugging/components/tab-header", true);
 loader.lazyRequireGetter(this, "Services");
 
 loader.lazyImporter(this, "Task", "resource://gre/modules/Task.jsm");
@@ -20,8 +22,8 @@ const Strings = Services.strings.createBundle(
   "chrome://devtools/locale/aboutdebugging.properties");
 const WorkerIcon = "chrome://devtools/skin/images/debugging-workers.svg";
 
-exports.WorkersComponent = React.createClass({
-  displayName: "WorkersComponent",
+exports.WorkersTab = React.createClass({
+  displayName: "WorkersTab",
 
   getInitialState() {
     return {
@@ -47,22 +49,30 @@ exports.WorkersComponent = React.createClass({
   },
 
   render() {
-    let client = this.props.client;
-    let workers = this.state.workers;
-    return React.createElement("div", { className: "inverted-icons" },
-      React.createElement(TargetListComponent, {
-        id: "service-workers",
-        name: Strings.GetStringFromName("serviceWorkers"),
-        targets: workers.service, client }),
-      React.createElement(TargetListComponent, {
-        id: "shared-workers",
-        name: Strings.GetStringFromName("sharedWorkers"),
-        targets: workers.shared, client }),
-      React.createElement(TargetListComponent, {
-        id: "other-workers",
-        name: Strings.GetStringFromName("otherWorkers"),
-        targets: workers.other, client })
-    );
+    let { client } = this.props;
+    let { workers } = this.state;
+
+    return React.createElement(
+      "div", { id: "tab-workers", className: "tab", role: "tabpanel",
+        "aria-labelledby": "tab-workers-header-name" },
+        React.createElement(TabHeader, {
+          id: "tab-workers-header-name",
+          name: Strings.GetStringFromName("workers")}),
+        React.createElement(
+          "div", { id: "workers", className: "inverted-icons" },
+          React.createElement(TargetList, {
+            id: "service-workers",
+            name: Strings.GetStringFromName("serviceWorkers"),
+            targets: workers.service, client }),
+          React.createElement(TargetList, {
+            id: "shared-workers",
+            name: Strings.GetStringFromName("sharedWorkers"),
+            targets: workers.shared, client }),
+          React.createElement(TargetList, {
+            id: "other-workers",
+            name: Strings.GetStringFromName("otherWorkers"),
+            targets: workers.other, client }))
+      );
   },
 
   update() {
diff --git a/devtools/client/aboutdebugging/initializer.js b/devtools/client/aboutdebugging/initializer.js
new file mode 100644
index 000000000000..433a0f515868
--- /dev/null
+++ b/devtools/client/aboutdebugging/initializer.js
@@ -0,0 +1,55 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* eslint-env browser */
+/* global DebuggerClient, DebuggerServer, React */
+
+"use strict";
+
+const { loader } = Components.utils.import(
+  "resource://devtools/shared/Loader.jsm", {});
+
+loader.lazyRequireGetter(this, "DebuggerClient",
+  "devtools/shared/client/main", true);
+loader.lazyRequireGetter(this, "DebuggerServer",
+  "devtools/server/main", true);
+loader.lazyRequireGetter(this, "Telemetry",
+  "devtools/client/shared/telemetry");
+loader.lazyRequireGetter(this, "AboutDebuggingApp",
+  "devtools/client/aboutdebugging/components/aboutdebugging", true);
+
+var AboutDebugging = {
+  init() {
+    if (!DebuggerServer.initialized) {
+      DebuggerServer.init();
+      DebuggerServer.addBrowserActors();
+    }
+    DebuggerServer.allowChromeProcess = true;
+    this.client = new DebuggerClient(DebuggerServer.connectPipe());
+
+    this.client.connect().then(() => {
+      let client = this.client;
+      let telemetry = new Telemetry();
+      React.render(React.createElement(AboutDebuggingApp,
+        { client, telemetry, window }), document.querySelector("#body"));
+    });
+  },
+
+  destroy() {
+    React.unmountComponentAtNode(document.querySelector("#body"));
+
+    this.client.close();
+    this.client = null;
+  },
+};
+
+window.addEventListener("DOMContentLoaded", function load() {
+  window.removeEventListener("DOMContentLoaded", load);
+  AboutDebugging.init();
+});
+
+window.addEventListener("unload", function unload() {
+  window.removeEventListener("unload", unload);
+  AboutDebugging.destroy();
+});
diff --git a/devtools/client/aboutdebugging/test/browser_service_workers.js b/devtools/client/aboutdebugging/test/browser_service_workers.js
index c75556400679..f45b60cfd586 100644
--- a/devtools/client/aboutdebugging/test/browser_service_workers.js
+++ b/devtools/client/aboutdebugging/test/browser_service_workers.js
@@ -26,6 +26,7 @@ add_task(function* () {
   let swTab = yield addTab(TAB_URL);
 
   let serviceWorkersElement = document.getElementById("service-workers");
+
   yield waitForMutation(serviceWorkersElement, { childList: true });
 
   // Check that the service worker appears in the UI
diff --git a/devtools/client/aboutdebugging/test/head.js b/devtools/client/aboutdebugging/test/head.js
index 01e13e0267a0..231132cd9415 100644
--- a/devtools/client/aboutdebugging/test/head.js
+++ b/devtools/client/aboutdebugging/test/head.js
@@ -21,19 +21,22 @@ registerCleanupFunction(() => {
   DevToolsUtils.testing = false;
 });
 
-function openAboutDebugging(page) {
+function* openAboutDebugging(page) {
   info("opening about:debugging");
   let url = "about:debugging";
   if (page) {
     url += "#" + page;
   }
-  return addTab(url).then(tab => {
-    let browser = tab.linkedBrowser;
-    return {
-      tab,
-      document: browser.contentDocument,
-    };
-  });
+
+  let tab = yield addTab(url);
+  let browser = tab.linkedBrowser;
+  let document = browser.contentDocument;
+
+  if (!document.querySelector(".app")) {
+    yield waitForMutation(document.body, { childList: true });
+  }
+
+  return { tab, document };
 }
 
 function closeAboutDebugging(tab) {
diff --git a/devtools/client/animationinspector/animation-controller.js b/devtools/client/animationinspector/animation-controller.js
index cc68a600d725..a283f6a75413 100644
--- a/devtools/client/animationinspector/animation-controller.js
+++ b/devtools/client/animationinspector/animation-controller.js
@@ -184,7 +184,7 @@ var AnimationsController = {
     this.nodeFront = null;
 
     // Finish releasing players that haven't been released yet.
-    yield Promise.all(this.nonBlockingPlayerReleases);
+    yield promise.all(this.nonBlockingPlayerReleases);
 
     if (this.animationsFront) {
       this.animationsFront.destroy();
diff --git a/devtools/client/animationinspector/animation-panel.js b/devtools/client/animationinspector/animation-panel.js
index 679eed936bd4..0b5265daac4b 100644
--- a/devtools/client/animationinspector/animation-panel.js
+++ b/devtools/client/animationinspector/animation-panel.js
@@ -258,8 +258,6 @@ var AnimationsPanel = {
    * the various components again.
    */
   refreshAnimationsUI: Task.async(function*() {
-    let done = gInspector.updating("animationspanel");
-
     // Empty the whole panel first.
     this.togglePlayers(true);
 
@@ -278,12 +276,10 @@ var AnimationsPanel = {
     if (!AnimationsController.animationPlayers.length) {
       this.togglePlayers(false);
       this.emit(this.UI_UPDATED_EVENT);
-      done();
       return;
     }
 
     this.emit(this.UI_UPDATED_EVENT);
-    done();
   })
 };
 
diff --git a/devtools/client/inspector/markup/test/browser_markup_keybindings_04.js b/devtools/client/inspector/markup/test/browser_markup_keybindings_04.js
index c165a62f1de9..ffa81aead6bb 100644
--- a/devtools/client/inspector/markup/test/browser_markup_keybindings_04.js
+++ b/devtools/client/inspector/markup/test/browser_markup_keybindings_04.js
@@ -1,5 +1,4 @@
 /* vim: set ts=2 et sw=2 tw=80: */
-/* global nsContextMenu*/
 /* Any copyright is dedicated to the Public Domain.
  http://creativecommons.org/publicdomain/zero/1.0/ */
 
@@ -17,7 +16,7 @@ add_task(function*() {
   let {inspector, testActor} = yield openInspectorForURL(TEST_URL);
 
   info("Select the test node with the browser ctx menu");
-  yield selectWithBrowserMenu(inspector);
+  yield clickOnInspectMenuItem(testActor, "div");
   assertNodeSelected(inspector, "div");
 
   info("Press arrowUp to focus <body> " +
@@ -47,27 +46,6 @@ function selectPreviousNodeWithArrowUp(inspector) {
   return Promise.all([onUpdated, onNodeHighlighted]);
 }
 
-function* selectWithBrowserMenu(inspector) {
-  let contentAreaContextMenu = document.querySelector("#contentAreaContextMenu");
-  let contextOpened = once(contentAreaContextMenu, "popupshown");
-
-  yield BrowserTestUtils.synthesizeMouseAtCenter("div", {
-    type: "contextmenu",
-    button: 2
-  }, gBrowser.selectedBrowser);
-
-  yield contextOpened;
-
-  yield gContextMenu.inspectNode();
-
-  let contextClosed = once(contentAreaContextMenu, "popuphidden");
-  contentAreaContextMenu.hidden = true;
-  contentAreaContextMenu.hidePopup();
-
-  yield inspector.once("inspector-updated");
-  yield contextClosed;
-}
-
 function* selectWithElementPicker(inspector, testActor) {
   yield startPicker(inspector.toolbox);
 
diff --git a/devtools/client/inspector/rules/test/browser.ini b/devtools/client/inspector/rules/test/browser.ini
index 71291874e512..7e3f0579ba33 100644
--- a/devtools/client/inspector/rules/test/browser.ini
+++ b/devtools/client/inspector/rules/test/browser.ini
@@ -68,7 +68,7 @@ support-files =
 [browser_rules_completion-popup-hidden-after-navigation.js]
 [browser_rules_content_01.js]
 [browser_rules_content_02.js]
-skip-if = e10s # Bug 1039528: "inspect element" contextual-menu doesn't work with e10s
+skip-if = e10s && debug && os == 'win' # Bug 1250058 - Docshell leak on win debug e10s
 [browser_rules_context-menu-show-mdn-docs-01.js]
 [browser_rules_context-menu-show-mdn-docs-02.js]
 [browser_rules_context-menu-show-mdn-docs-03.js]
diff --git a/devtools/client/inspector/rules/test/browser_rules_content_02.js b/devtools/client/inspector/rules/test/browser_rules_content_02.js
index 6d4849c5218f..5c9d31409fa3 100644
--- a/devtools/client/inspector/rules/test/browser_rules_content_02.js
+++ b/devtools/client/inspector/rules/test/browser_rules_content_02.js
@@ -19,34 +19,12 @@ const STRINGS = Services.strings
   .createBundle("chrome://devtools-shared/locale/styleinspector.properties");
 
 add_task(function*() {
-  yield addTab("data:text/html;charset=utf-8," + CONTENT);
+  let tab = yield addTab("data:text/html;charset=utf-8," + CONTENT);
 
-  info("Getting the test element");
-  let element = getNode("span");
+  let testActor = yield getTestActorWithoutToolbox(tab);
+  let inspector = yield clickOnInspectMenuItem(testActor, "span");
 
-  info("Opening the inspector using the content context-menu");
-  let onInspectorReady = gDevTools.once("inspector-ready");
-
-  document.popupNode = element;
-  let contentAreaContextMenu = document.getElementById("contentAreaContextMenu");
-  let contextMenu = new nsContextMenu(contentAreaContextMenu);
-  yield contextMenu.inspectNode();
-
-  // Clean up context menu:
-  contextMenu.hiding();
-
-  yield onInspectorReady;
-
-  let target = TargetFactory.forTab(gBrowser.selectedTab);
-  let toolbox = gDevTools.getToolbox(target);
-
-  info("Getting the inspector and making sure it is fully updated");
-  let inspector = toolbox.getPanel("inspector");
-  yield inspector.once("inspector-updated");
-
-  let view = inspector.ruleview.view;
-
-  checkRuleViewContent(view);
+  checkRuleViewContent(inspector.ruleview.view);
 });
 
 function checkRuleViewContent({styleDocument}) {
@@ -81,3 +59,4 @@ function checkRuleViewContent({styleDocument}) {
     is(propertyValues.length, 1, "There's only one property value, as expected");
   }
 }
+
diff --git a/devtools/client/inspector/rules/test/browser_rules_eyedropper.js b/devtools/client/inspector/rules/test/browser_rules_eyedropper.js
index 385d2a680f21..55a46f913cc1 100644
--- a/devtools/client/inspector/rules/test/browser_rules_eyedropper.js
+++ b/devtools/client/inspector/rules/test/browser_rules_eyedropper.js
@@ -10,10 +10,10 @@ Services.telemetry.canRecordExtended = true;
 registerCleanupFunction(function() {
   Services.telemetry.canRecordExtended = oldCanRecord;
 });
-const HISTOGRAM_ID = "DEVTOOLS_PICKER_EYEDROPPER_OPENED_BOOLEAN";
+const HISTOGRAM_ID = "DEVTOOLS_PICKER_EYEDROPPER_OPENED_COUNT";
 const FLAG_HISTOGRAM_ID = "DEVTOOLS_PICKER_EYEDROPPER_OPENED_PER_USER_FLAG";
 const EXPECTED_TELEMETRY = {
-  "DEVTOOLS_PICKER_EYEDROPPER_OPENED_BOOLEAN": 2,
+  "DEVTOOLS_PICKER_EYEDROPPER_OPENED_COUNT": 2,
   "DEVTOOLS_PICKER_EYEDROPPER_OPENED_PER_USER_FLAG": 1
 };
 
@@ -122,7 +122,7 @@ function checkTelemetry() {
     let histogram = Services.telemetry.getHistogramById(histogramId);
     let snapshot = histogram.snapshot();
 
-    is(snapshot.counts[1], expected,
+    is(snapshot.sum, expected,
       "eyedropper telemetry value correct for " + histogramId);
   }
 }
diff --git a/devtools/client/inspector/shared/test/head.js b/devtools/client/inspector/shared/test/head.js
index 5857f12c7f29..c8421e8496d3 100644
--- a/devtools/client/inspector/shared/test/head.js
+++ b/devtools/client/inspector/shared/test/head.js
@@ -217,7 +217,9 @@ var openInspector = Task.async(function*() {
   inspector = toolbox.getPanel("inspector");
 
   info("Waiting for the inspector to update");
-  yield inspector.once("inspector-updated");
+  if (inspector._updateProgress) {
+    yield inspector.once("inspector-updated");
+  }
 
   return {
     toolbox: toolbox,
diff --git a/devtools/client/inspector/test/browser.ini b/devtools/client/inspector/test/browser.ini
index 0e846dbeb28f..dcbf593372ce 100644
--- a/devtools/client/inspector/test/browser.ini
+++ b/devtools/client/inspector/test/browser.ini
@@ -80,7 +80,7 @@ skip-if = e10s # GCLI isn't e10s compatible. See bug 1128988.
 [browser_inspector_iframe-navigation.js]
 [browser_inspector_infobar_01.js]
 [browser_inspector_initialization.js]
-skip-if = e10s && debug && os == 'win'
+skip-if = e10s && debug && os == 'win' # Bug 1250058 - Docshell leak on win debug e10s
 [browser_inspector_inspect-object-element.js]
 [browser_inspector_invalidate.js]
 [browser_inspector_keyboard-shortcuts-copy-outerhtml.js]
diff --git a/devtools/client/inspector/test/browser_inspector_initialization.js b/devtools/client/inspector/test/browser_inspector_initialization.js
index dd9784458794..e9c03057ed03 100644
--- a/devtools/client/inspector/test/browser_inspector_initialization.js
+++ b/devtools/client/inspector/test/browser_inspector_initialization.js
@@ -114,27 +114,3 @@ function* testBreadcrumbs(selector, inspector) {
   ok(button, "A crumbs is checked=true");
   is(button.getAttribute("tooltiptext"), expectedText, "Crumb refers to the right node");
 }
-
-function* clickOnInspectMenuItem(testActor, selector) {
-  info("Showing the contextual menu on node " + selector);
-  let contentAreaContextMenu = document.querySelector("#contentAreaContextMenu");
-  let contextOpened = once(contentAreaContextMenu, "popupshown");
-
-  yield testActor.synthesizeMouse({
-    selector: selector,
-    center: true,
-    options: {type: "contextmenu", button: 2}
-  });
-
-  yield contextOpened;
-
-  info("Triggering inspect action and hiding the menu.");
-  yield gContextMenu.inspectNode();
-
-  let contextClosed = once(contentAreaContextMenu, "popuphidden");
-  contentAreaContextMenu.hidePopup();
-
-  info("Waiting for inspector to update.");
-  yield getActiveInspector().once("inspector-updated");
-  yield contextClosed;
-}
diff --git a/devtools/client/inspector/test/head.js b/devtools/client/inspector/test/head.js
index a1f4f578ef71..61d1f6ed2d95 100644
--- a/devtools/client/inspector/test/head.js
+++ b/devtools/client/inspector/test/head.js
@@ -175,6 +175,36 @@ function getActiveInspector() {
   return gDevTools.getToolbox(target).getPanel("inspector");
 }
 
+/**
+ * Right click on a node in the test page and click on the inspect menu item.
+ * @param {TestActor}
+ * @param {String} selector The selector for the node to click on in the page.
+ * @return {Promise} Resolves to the inspector when it has opened and is updated
+ */
+var clickOnInspectMenuItem = Task.async(function*(testActor, selector) {
+  info("Showing the contextual menu on node " + selector);
+  let contentAreaContextMenu = document.querySelector("#contentAreaContextMenu");
+  let contextOpened = once(contentAreaContextMenu, "popupshown");
+
+  yield testActor.synthesizeMouse({
+    selector: selector,
+    center: true,
+    options: {type: "contextmenu", button: 2}
+  });
+
+  yield contextOpened;
+
+  info("Triggering the inspect action");
+  yield gContextMenu.inspectNode();
+
+  info("Hiding the menu");
+  let contextClosed = once(contentAreaContextMenu, "popuphidden");
+  contentAreaContextMenu.hidePopup();
+  yield contextClosed;
+
+  return getActiveInspector();
+});
+
 /**
  * Open the toolbox, with the inspector tool visible, and the one of the sidebar
  * tabs selected.
diff --git a/devtools/client/jar.mn b/devtools/client/jar.mn
index 28f9c97037f7..619cebf466d9 100644
--- a/devtools/client/jar.mn
+++ b/devtools/client/jar.mn
@@ -138,7 +138,7 @@ devtools.jar:
     content/eyedropper/nocursor.css (eyedropper/nocursor.css)
     content/aboutdebugging/aboutdebugging.xhtml (aboutdebugging/aboutdebugging.xhtml)
     content/aboutdebugging/aboutdebugging.css (aboutdebugging/aboutdebugging.css)
-    content/aboutdebugging/aboutdebugging.js (aboutdebugging/aboutdebugging.js)
+    content/aboutdebugging/initializer.js (aboutdebugging/initializer.js)
     content/responsive.html/index.xhtml (responsive.html/index.xhtml)
     content/responsive.html/index.js (responsive.html/index.js)
 %   skin devtools classic/1.0 %skin/
diff --git a/devtools/client/locales/en-US/aboutdebugging.dtd b/devtools/client/locales/en-US/aboutdebugging.dtd
index 138e54267b64..273794954294 100644
--- a/devtools/client/locales/en-US/aboutdebugging.dtd
+++ b/devtools/client/locales/en-US/aboutdebugging.dtd
@@ -3,8 +3,3 @@
    - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
 
 <!ENTITY aboutDebugging.title                      "about:debugging">
-<!ENTITY aboutDebugging.addons                     "Add-ons">
-<!ENTITY aboutDebugging.addonDebugging.label       "Enable add-on debugging">
-<!ENTITY aboutDebugging.addonDebugging.tooltip     "Turning this on will allow you to debug add-ons and various other parts of the browser chrome">
-<!ENTITY aboutDebugging.loadTemporaryAddon         "Load Temporary Add-on">
-<!ENTITY aboutDebugging.workers                    "Workers">
diff --git a/devtools/client/locales/en-US/aboutdebugging.properties b/devtools/client/locales/en-US/aboutdebugging.properties
index 67a3e99864d1..94bafd7ab273 100644
--- a/devtools/client/locales/en-US/aboutdebugging.properties
+++ b/devtools/client/locales/en-US/aboutdebugging.properties
@@ -4,10 +4,17 @@
 
 debug = Debug
 
+addons = Add-ons
+addonDebugging.label = Enable add-on debugging
+addonDebugging.tooltip = Turning this on will allow you to debug add-ons and various other parts of the browser chrome
+loadTemporaryAddon = Load Temporary Add-on
 extensions = Extensions
 selectAddonFromFile = Select Add-on Directory or XPI File
+
+workers = Workers
 serviceWorkers = Service Workers
 sharedWorkers = Shared Workers
 otherWorkers = Other Workers
 
 nothing = Nothing yet.
+
diff --git a/devtools/client/memory/constants.js b/devtools/client/memory/constants.js
index 023b91713246..f4a7ee378ef1 100644
--- a/devtools/client/memory/constants.js
+++ b/devtools/client/memory/constants.js
@@ -110,7 +110,7 @@ const OBJECT_CLASS = { by: "objectClass", then: COUNT, other: COUNT };
 
 const breakdowns = exports.breakdowns = {
   coarseType: {
-    displayName: "Coarse Type",
+    displayName: "Type",
     get tooltip() {
       // Importing down here is necessary because of the circular dependency
       // this introduces with `./utils.js`.
@@ -131,31 +131,13 @@ const breakdowns = exports.breakdowns = {
   },
 
   allocationStack: {
-    displayName: "Allocation Stack",
+    displayName: "Call Stack",
     get tooltip() {
       const { L10N } = require("./utils");
       return L10N.getStr("breakdowns.allocationStack.tooltip");
     },
     breakdown: ALLOCATION_STACK,
   },
-
-  objectClass: {
-    displayName: "Object Class",
-    get tooltip() {
-      const { L10N } = require("./utils");
-      return L10N.getStr("breakdowns.objectClass.tooltip");
-    },
-    breakdown: OBJECT_CLASS,
-  },
-
-  internalType: {
-    displayName: "Internal Type",
-    get tooltip() {
-      const { L10N } = require("./utils");
-      return L10N.getStr("breakdowns.internalType.tooltip");
-    },
-    breakdown: INTERNAL_TYPE,
-  },
 };
 
 const DOMINATOR_TREE_LABEL_COARSE_TYPE = {
@@ -175,7 +157,7 @@ const DOMINATOR_TREE_LABEL_COARSE_TYPE = {
 
 const dominatorTreeBreakdowns = exports.dominatorTreeBreakdowns = {
   coarseType: {
-    displayName: "Coarse Type",
+    displayName: "Type",
     get tooltip() {
       const { L10N } = require("./utils");
       return L10N.getStr("dominatorTreeBreakdowns.coarseType.tooltip");
@@ -184,7 +166,7 @@ const dominatorTreeBreakdowns = exports.dominatorTreeBreakdowns = {
   },
 
   allocationStack: {
-    displayName: "Allocation Stack",
+    displayName: "Call Stack",
     get tooltip() {
       const { L10N } = require("./utils");
       return L10N.getStr("dominatorTreeBreakdowns.allocationStack.tooltip");
@@ -195,15 +177,6 @@ const dominatorTreeBreakdowns = exports.dominatorTreeBreakdowns = {
       noStack: DOMINATOR_TREE_LABEL_COARSE_TYPE,
     },
   },
-
-  internalType: {
-    displayName: "Internal Type",
-    get tooltip() {
-      const { L10N } = require("./utils");
-      return L10N.getStr("dominatorTreeBreakdowns.internalType.tooltip");
-    },
-    breakdown: INTERNAL_TYPE,
-  },
 };
 
 /*** View States **************************************************************/
diff --git a/devtools/client/memory/models.js b/devtools/client/memory/models.js
index 1600e392364c..6bcce75a88ac 100644
--- a/devtools/client/memory/models.js
+++ b/devtools/client/memory/models.js
@@ -50,7 +50,7 @@ function catchAndIgnore(fn) {
  * @see `js/src/doc/Debugger/Debugger.Memory.md`
  */
 let breakdownModel = exports.breakdown = PropTypes.shape({
-  by: PropTypes.oneOf(["coarseType", "allocationStack", "objectClass", "internalType"]).isRequired,
+  by: PropTypes.string.isRequired,
 });
 
 let censusModel = exports.censusModel = PropTypes.shape({
diff --git a/devtools/client/memory/telemetry.js b/devtools/client/memory/telemetry.js
index 47b415e943a0..f37d49f3f8e9 100644
--- a/devtools/client/memory/telemetry.js
+++ b/devtools/client/memory/telemetry.js
@@ -61,10 +61,6 @@ exports.countCensus = makeInfallible(function ({ inverted, filter, diffing, brea
     histogram.add(COARSE_TYPE);
   } else if (breakdown === breakdowns.allocationStack.breakdown) {
     histogram.add(ALLOCATION_STACK);
-  } else if (breakdown === breakdowns.objectClass.breakdown) {
-    histogram.add(OBJECT_CLASS);
-  } else if (breakdown === breakdowns.internalType.breakdown) {
-    histogram.add(INTERNAL_TYPE);
   } else {
     histogram.add(CUSTOM);
   }
@@ -91,8 +87,6 @@ exports.countDominatorTree = makeInfallible(function ({ breakdown }) {
     histogram.add(COARSE_TYPE);
   } else if (breakdown === dominatorTreeBreakdowns.allocationStack.breakdown) {
     histogram.add(ALLOCATION_STACK);
-  } else if (breakdown === dominatorTreeBreakdowns.internalType.breakdown) {
-    histogram.add(INTERNAL_TYPE);
   } else {
     histogram.add(CUSTOM);
   }
diff --git a/devtools/client/memory/test/browser/browser_memory_breakdowns_01.js b/devtools/client/memory/test/browser/browser_memory_breakdowns_01.js
index 70d358b7124a..e8f352f6c16c 100644
--- a/devtools/client/memory/test/browser/browser_memory_breakdowns_01.js
+++ b/devtools/client/memory/test/browser/browser_memory_breakdowns_01.js
@@ -19,13 +19,9 @@ this.test = makeMemoryTest(TEST_URL, function* ({ tab, panel }) {
   info("Check coarse type heap view");
   ["objects", "other", "scripts", "strings"].forEach(findNameCell);
 
-  yield setBreakdown(panel.panelWin, "objectClass");
-  info("Check object class heap view");
-  ["Function", "Object"].forEach(findNameCell);
-
-  yield setBreakdown(panel.panelWin, "internalType");
-  info("Check internal type heap view");
-  ["JSObject"].forEach(findNameCell);
+  yield setBreakdown(panel.panelWin, "allocationStack");
+  info("Check allocation stack heap view");
+  [L10N.getStr("tree-item.nostack")].forEach(findNameCell);
 
   function findNameCell (name) {
     let el = Array.prototype.find.call($$(".tree .heap-tree-item-name span"), el => el.textContent === name);
diff --git a/devtools/client/memory/test/browser/browser_memory_percents_01.js b/devtools/client/memory/test/browser/browser_memory_percents_01.js
index 93ae21924d00..c6591fbb31bf 100644
--- a/devtools/client/memory/test/browser/browser_memory_percents_01.js
+++ b/devtools/client/memory/test/browser/browser_memory_percents_01.js
@@ -28,11 +28,8 @@ this.test = makeMemoryTest(TEST_URL, function* ({ tab, panel }) {
   const doc = panel.panelWin.document;
 
   yield dispatch(takeSnapshotAndCensus(front, heapWorker));
-  yield dispatch(breakdownActions.setBreakdownAndRefresh(heapWorker,
-                                                         breakdowns.objectClass.breakdown));
-
-  is(getState().breakdown.by, "objectClass",
-     "Should be using object class breakdown");
+  is(getState().breakdown.by, "coarseType",
+     "Should be using coarse type breakdown");
 
   const bytesCells = [...doc.querySelectorAll(".heap-tree-item-bytes")];
   checkCells(bytesCells);
diff --git a/devtools/client/memory/test/browser/head.js b/devtools/client/memory/test/browser/head.js
index a9d7f445e688..dec169949493 100644
--- a/devtools/client/memory/test/browser/head.js
+++ b/devtools/client/memory/test/browser/head.js
@@ -14,7 +14,7 @@ Services.scriptloader.loadSubScript(
   this);
 
 var { snapshotState: states } = require("devtools/client/memory/constants");
-var { breakdownEquals, breakdownNameToSpec } = require("devtools/client/memory/utils");
+var { breakdownEquals, breakdownNameToSpec, L10N } = require("devtools/client/memory/utils");
 
 Services.prefs.setBoolPref("devtools.memory.enabled", true);
 
diff --git a/devtools/client/memory/test/unit/head.js b/devtools/client/memory/test/unit/head.js
index 3f9d9ef31441..e91f240c6898 100644
--- a/devtools/client/memory/test/unit/head.js
+++ b/devtools/client/memory/test/unit/head.js
@@ -23,6 +23,7 @@ var HeapSnapshotFileUtils = require("devtools/shared/heapsnapshot/HeapSnapshotFi
 var HeapAnalysesClient = require("devtools/shared/heapsnapshot/HeapAnalysesClient");
 var { addDebuggerToGlobal } = require("resource://gre/modules/jsdebugger.jsm");
 var Store = require("devtools/client/memory/store");
+var { L10N } = require("devtools/client/memory/utils");
 var SYSTEM_PRINCIPAL = Cc["@mozilla.org/systemprincipal;1"].createInstance(Ci.nsIPrincipal);
 
 function dumpn(msg) {
@@ -80,11 +81,8 @@ function isBreakdownType (report, type) {
   switch (type) {
     case "coarseType":
       return report.children.find(c => c.name === "objects");
-    case "objectClass":
-      return report.children.find(c => c.name === "Function");
-    case "internalType":
-      return report.children.find(c => c.name === "js::BaseShape") &&
-             !report.children.find(c => c.name === "objects");
+    case "allocationStack":
+      return report.children.find(c => c.name === "noStack");
     default:
       throw new Error(`isBreakdownType does not yet support ${type}`);
   }
diff --git a/devtools/client/memory/test/unit/test_action-set-breakdown-and-refresh-01.js b/devtools/client/memory/test/unit/test_action-set-breakdown-and-refresh-01.js
index e93de79fb6cb..831cd8a96c65 100644
--- a/devtools/client/memory/test/unit/test_action-set-breakdown-and-refresh-01.js
+++ b/devtools/client/memory/test/unit/test_action-set-breakdown-and-refresh-01.js
@@ -25,8 +25,8 @@ add_task(function *() {
 
   // Test default breakdown with no snapshots
   equal(getState().breakdown.by, "coarseType", "default coarseType breakdown selected at start.");
-  dispatch(setBreakdownAndRefresh(heapWorker, breakdowns.objectClass.breakdown));
-  equal(getState().breakdown.by, "objectClass", "breakdown changed with no snapshots");
+  dispatch(setBreakdownAndRefresh(heapWorker, breakdowns.allocationStack.breakdown));
+  equal(getState().breakdown.by, "allocationStack", "breakdown changed with no snapshots");
 
   // Test invalid breakdowns
   ok(getState().errors.length === 0, "No error actions in the queue.");
@@ -34,13 +34,13 @@ add_task(function *() {
   yield waitUntilState(store, () => getState().errors.length === 1);
   ok(true, "Emits an error action when passing in an invalid breakdown object");
 
-  equal(getState().breakdown.by, "objectClass",
+  equal(getState().breakdown.by, "allocationStack",
     "current breakdown unchanged when passing invalid breakdown");
 
   // Test new snapshots
   dispatch(takeSnapshotAndCensus(front, heapWorker));
   yield waitUntilSnapshotState(store, [states.SAVED_CENSUS]);
-  ok(isBreakdownType(getState().snapshots[0].census.report, "objectClass"),
+  ok(isBreakdownType(getState().snapshots[0].census.report, "allocationStack"),
     "New snapshots use the current, non-default breakdown");
 
 
@@ -57,21 +57,24 @@ add_task(function *() {
   // Updates when changing breakdown during `SAVING_CENSUS`
   dispatch(takeSnapshotAndCensus(front, heapWorker));
   yield waitUntilSnapshotState(store, [states.SAVED_CENSUS, states.SAVED_CENSUS, states.SAVING_CENSUS]);
-  dispatch(setBreakdownAndRefresh(heapWorker, breakdowns.objectClass.breakdown));
+  dispatch(setBreakdownAndRefresh(heapWorker, breakdowns.allocationStack.breakdown));
   yield waitUntilSnapshotState(store, [states.SAVED_CENSUS, states.SAVED_CENSUS, states.SAVED_CENSUS]);
 
-  ok(breakdownEquals(getState().snapshots[2].census.breakdown, breakdowns.objectClass.breakdown),
+  ok(breakdownEquals(getState().snapshots[2].census.breakdown, breakdowns.allocationStack.breakdown),
     "Breakdown can be changed while saving census, stores updated breakdown in snapshot");
-  ok(isBreakdownType(getState().snapshots[2].census.report, "objectClass"),
+  ok(isBreakdownType(getState().snapshots[2].census.report, "allocationStack"),
     "Breakdown can be changed while saving census, uses updated breakdown in census");
 
   // Updates census on currently selected snapshot when changing breakdown
   ok(getState().snapshots[2].selected, "Third snapshot currently selected");
-  dispatch(setBreakdownAndRefresh(heapWorker, breakdowns.internalType.breakdown));
-  yield waitUntilState(store, () => isBreakdownType(getState().snapshots[2].census.report, "internalType"));
-  ok(isBreakdownType(getState().snapshots[2].census.report, "internalType"),
+  dispatch(setBreakdownAndRefresh(heapWorker, breakdowns.coarseType.breakdown));
+  yield waitUntilState(store, () => isBreakdownType(getState().snapshots[2].census.report, "coarseType"));
+  ok(isBreakdownType(getState().snapshots[2].census.report, "coarseType"),
     "Snapshot census updated when changing breakdowns after already generating one census");
 
+  dispatch(setBreakdownAndRefresh(heapWorker, breakdowns.allocationStack.breakdown));
+  yield waitUntilState(store, () => isBreakdownType(getState().snapshots[2].census.report, "allocationStack"));
+
   // Does not update unselected censuses
   ok(!getState().snapshots[1].selected, "Second snapshot unselected currently");
   ok(breakdownEquals(getState().snapshots[1].census.breakdown, breakdowns.coarseType.breakdown),
@@ -85,10 +88,10 @@ add_task(function *() {
   yield waitUntilSnapshotState(store, [states.SAVED_CENSUS, states.SAVED_CENSUS, states.SAVED_CENSUS]);
 
   ok(getState().snapshots[1].selected, "Second snapshot selected currently");
-  ok(breakdownEquals(getState().snapshots[1].census.breakdown, breakdowns.internalType.breakdown),
-    "Second snapshot using `internalType` breakdown and updated to correct breakdown");
-  ok(isBreakdownType(getState().snapshots[1].census.report, "internalType"),
-     "Second snapshot using `internalType` for census and updated to correct breakdown");
+  ok(breakdownEquals(getState().snapshots[1].census.breakdown, breakdowns.allocationStack.breakdown),
+    "Second snapshot using `allocationStack` breakdown and updated to correct breakdown");
+  ok(isBreakdownType(getState().snapshots[1].census.report, "allocationStack"),
+     "Second snapshot using `allocationStack` for census and updated to correct breakdown");
 
   heapWorker.destroy();
   yield front.detach();
diff --git a/devtools/client/memory/test/unit/test_action-set-breakdown.js b/devtools/client/memory/test/unit/test_action-set-breakdown.js
index 26d185abce6e..fd692cd39c07 100644
--- a/devtools/client/memory/test/unit/test_action-set-breakdown.js
+++ b/devtools/client/memory/test/unit/test_action-set-breakdown.js
@@ -24,8 +24,8 @@ add_task(function *() {
 
   // Test default breakdown with no snapshots
   equal(getState().breakdown.by, "coarseType", "default coarseType breakdown selected at start.");
-  dispatch(setBreakdown(breakdowns.objectClass.breakdown));
-  equal(getState().breakdown.by, "objectClass", "breakdown changed with no snapshots");
+  dispatch(setBreakdown(breakdowns.allocationStack.breakdown));
+  equal(getState().breakdown.by, "allocationStack", "breakdown changed with no snapshots");
 
   // Test invalid breakdowns
   try {
@@ -34,12 +34,12 @@ add_task(function *() {
   } catch (e) {
     ok(true, "Throws when passing in an invalid breakdown object");
   }
-  equal(getState().breakdown.by, "objectClass",
+  equal(getState().breakdown.by, "allocationStack",
     "current breakdown unchanged when passing invalid breakdown");
 
   // Test new snapshots
   dispatch(takeSnapshotAndCensus(front, heapWorker));
   yield waitUntilSnapshotState(store, [states.SAVED_CENSUS]);
-  ok(isBreakdownType(getState().snapshots[0].census.report, "objectClass"),
+  ok(isBreakdownType(getState().snapshots[0].census.report, "allocationStack"),
     "New snapshots use the current, non-default breakdown");
 });
diff --git a/devtools/client/memory/test/unit/test_action_diffing_05.js b/devtools/client/memory/test/unit/test_action_diffing_05.js
index 2a8c61039d6b..d664058f03d2 100644
--- a/devtools/client/memory/test/unit/test_action_diffing_05.js
+++ b/devtools/client/memory/test/unit/test_action_diffing_05.js
@@ -71,7 +71,7 @@ add_task(function *() {
       name: "changing breakdowns",
       func: () =>
         dispatch(setBreakdownAndRefresh(heapWorker,
-                                        breakdowns.objectClass.breakdown))
+                                        breakdowns.allocationStack.breakdown))
     }
   ];
 
diff --git a/devtools/client/memory/test/unit/test_dominator_trees_08.js b/devtools/client/memory/test/unit/test_dominator_trees_08.js
index aa42df34c038..22e8f5446e88 100644
--- a/devtools/client/memory/test/unit/test_dominator_trees_08.js
+++ b/devtools/client/memory/test/unit/test_dominator_trees_08.js
@@ -55,10 +55,10 @@ add_task(function *() {
         getState().snapshots[0].dominatorTree.breakdown,
         "and the newly computed dominator tree has that breakdown");
 
-  // Switch to the internalType breakdown.
+  // Switch to the allocationStack breakdown.
   dispatch(setDominatorTreeBreakdownAndRefresh(
     heapWorker,
-    dominatorTreeBreakdowns.internalType.breakdown));
+    dominatorTreeBreakdowns.allocationStack.breakdown));
 
   yield waitUntilState(store, state =>
     state.snapshots[0].dominatorTree.state === dominatorTreeState.FETCHING);
@@ -69,10 +69,10 @@ add_task(function *() {
   yield waitUntilState(store, state =>
     state.snapshots[0].dominatorTree.state === dominatorTreeState.LOADED);
   equal(getState().snapshots[0].dominatorTree.breakdown,
-        dominatorTreeBreakdowns.internalType.breakdown,
-        "The new dominator tree's breakdown is internalType");
+        dominatorTreeBreakdowns.allocationStack.breakdown,
+        "The new dominator tree's breakdown is allocationStack");
   equal(getState().dominatorTreeBreakdown,
-        dominatorTreeBreakdowns.internalType.breakdown,
+        dominatorTreeBreakdowns.allocationStack.breakdown,
         "as is our requested dominator tree breakdown");
 
   heapWorker.destroy();
diff --git a/devtools/client/memory/test/unit/test_dominator_trees_09.js b/devtools/client/memory/test/unit/test_dominator_trees_09.js
index c5079753dc74..799fa3632f99 100644
--- a/devtools/client/memory/test/unit/test_dominator_trees_09.js
+++ b/devtools/client/memory/test/unit/test_dominator_trees_09.js
@@ -55,21 +55,21 @@ add_task(function *() {
         getState().snapshots[0].dominatorTree.breakdown,
         "and the newly computed dominator tree has that breakdown");
 
-  // Switch to the internalType breakdown while we are still fetching the
+  // Switch to the allocationStack breakdown while we are still fetching the
   // dominator tree.
   dispatch(setDominatorTreeBreakdownAndRefresh(
     heapWorker,
-    dominatorTreeBreakdowns.internalType.breakdown));
+    dominatorTreeBreakdowns.allocationStack.breakdown));
 
   // Wait for the dominator tree to finish being fetched.
   yield waitUntilState(store, state =>
     state.snapshots[0].dominatorTree.state === dominatorTreeState.LOADED);
 
   equal(getState().snapshots[0].dominatorTree.breakdown,
-        dominatorTreeBreakdowns.internalType.breakdown,
-        "The new dominator tree's breakdown is internalType");
+        dominatorTreeBreakdowns.allocationStack.breakdown,
+        "The new dominator tree's breakdown is allocationStack");
   equal(getState().dominatorTreeBreakdown,
-        dominatorTreeBreakdowns.internalType.breakdown,
+        dominatorTreeBreakdowns.allocationStack.breakdown,
         "as is our requested dominator tree breakdown");
 
   heapWorker.destroy();
diff --git a/devtools/client/responsive.html/components/moz.build b/devtools/client/responsive.html/components/moz.build
index 9a98dbe75c57..15c46620cda3 100644
--- a/devtools/client/responsive.html/components/moz.build
+++ b/devtools/client/responsive.html/components/moz.build
@@ -7,6 +7,7 @@
 DevToolsModules(
     'browser.js',
     'resizable-viewport.js',
+    'viewport-dimension.js',
     'viewport-toolbar.js',
     'viewport.js',
     'viewports.js',
diff --git a/devtools/client/responsive.html/components/resizable-viewport.js b/devtools/client/responsive.html/components/resizable-viewport.js
index 91a6623f174f..719fcf106dda 100644
--- a/devtools/client/responsive.html/components/resizable-viewport.js
+++ b/devtools/client/responsive.html/components/resizable-viewport.js
@@ -9,12 +9,13 @@
 const { DOM: dom, createClass, createFactory, PropTypes } =
   require("devtools/client/shared/vendor/react");
 
+const Constants = require("../constants");
 const Types = require("../types");
 const Browser = createFactory(require("./browser"));
 const ViewportToolbar = createFactory(require("./viewport-toolbar"));
 
-const VIEWPORT_MIN_WIDTH = 280;
-const VIEWPORT_MIN_HEIGHT = 280;
+const VIEWPORT_MIN_WIDTH = Constants.MIN_VIEWPORT_DIMENSION;
+const VIEWPORT_MIN_HEIGHT = Constants.MIN_VIEWPORT_DIMENSION;
 
 module.exports = createClass({
 
diff --git a/devtools/client/responsive.html/components/viewport-dimension.js b/devtools/client/responsive.html/components/viewport-dimension.js
new file mode 100644
index 000000000000..eb22003ce505
--- /dev/null
+++ b/devtools/client/responsive.html/components/viewport-dimension.js
@@ -0,0 +1,164 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const { DOM: dom, createClass, PropTypes } =
+  require("devtools/client/shared/vendor/react");
+
+const Constants = require("../constants");
+const Types = require("../types");
+
+module.exports = createClass({
+
+  displayName: "ViewportDimension",
+
+  propTypes: {
+    viewport: PropTypes.shape(Types.viewport).isRequired,
+    onResizeViewport: PropTypes.func.isRequired,
+  },
+
+  getInitialState() {
+    let { width, height } = this.props.viewport;
+
+    return {
+      width,
+      height,
+      isEditing: false,
+      isInvalid: false,
+    };
+  },
+
+  componentWillReceiveProps(nextProps) {
+    let { width, height } = nextProps.viewport;
+
+    this.setState({
+      width,
+      height,
+    });
+  },
+
+  validateInput(value) {
+    let isInvalid = true;
+
+    // Check the value is a number and greater than MIN_VIEWPORT_DIMENSION
+    if (/^\d{3,4}$/.test(value) &&
+        parseInt(value, 10) >= Constants.MIN_VIEWPORT_DIMENSION) {
+      isInvalid = false;
+    }
+
+    this.setState({
+      isInvalid,
+    });
+  },
+
+  onInputBlur() {
+    this.onInputSubmit();
+
+    this.setState({
+      isEditing: false,
+      inInvalid: false,
+    });
+  },
+
+  onInputChange({ target }) {
+    if (target.value.length > 4) {
+      return;
+    }
+
+    if (this.refs.widthInput == target) {
+      this.setState({ width: target.value });
+      this.validateInput(target.value);
+    }
+
+    if (this.refs.heightInput == target) {
+      this.setState({ height: target.value });
+      this.validateInput(target.value);
+    }
+  },
+
+  onInputFocus() {
+    this.setState({
+      isEditing: true,
+    });
+  },
+
+  onInputKeyUp({ target, keyCode }) {
+    // On Enter, submit the input
+    if (keyCode == 13) {
+      this.onInputSubmit();
+    }
+
+    // On Esc, blur the target
+    if (keyCode == 27) {
+      target.blur();
+    }
+  },
+
+  onInputSubmit() {
+    if (this.state.isInvalid) {
+      let { width, height } = this.props.viewport;
+
+      this.setState({
+        width,
+        height,
+        isInvalid: false,
+      });
+
+      return;
+    }
+
+    this.props.onResizeViewport(parseInt(this.state.width, 10),
+                                parseInt(this.state.height, 10));
+  },
+
+  render() {
+    let editableClass = "viewport-dimension-editable";
+    let inputClass = "viewport-dimension-input";
+
+    if (this.state.isEditing) {
+      editableClass += " editing";
+      inputClass += " editing";
+    }
+
+    if (this.state.isInvalid) {
+      editableClass += " invalid";
+    }
+
+    return dom.div(
+      {
+        className: "viewport-dimension",
+      },
+      dom.div(
+        {
+          className: editableClass,
+        },
+        dom.input({
+          ref: "widthInput",
+          className: inputClass,
+          size: 4,
+          value: this.state.width,
+          onBlur: this.onInputBlur,
+          onChange: this.onInputChange,
+          onFocus: this.onInputFocus,
+          onKeyUp: this.onInputKeyUp,
+        }),
+        dom.span({
+          className: "viewport-dimension-separator",
+        }, "×"),
+        dom.input({
+          ref: "heightInput",
+          className: inputClass,
+          size: 4,
+          value: this.state.height,
+          onBlur: this.onInputBlur,
+          onChange: this.onInputChange,
+          onFocus: this.onInputFocus,
+          onKeyUp: this.onInputKeyUp,
+        })
+      )
+    );
+  },
+
+});
diff --git a/devtools/client/responsive.html/components/viewport.js b/devtools/client/responsive.html/components/viewport.js
index 8f1767c40b9d..a0c711f8a47b 100644
--- a/devtools/client/responsive.html/components/viewport.js
+++ b/devtools/client/responsive.html/components/viewport.js
@@ -9,6 +9,7 @@ const { DOM: dom, createClass, createFactory, PropTypes } =
 
 const Types = require("../types");
 const ResizableViewport = createFactory(require("./resizable-viewport"));
+const ViewportDimension = createFactory(require("./viewport-dimension"));
 
 module.exports = createClass({
 
@@ -38,6 +39,10 @@ module.exports = createClass({
         viewport,
         onResizeViewport,
         onRotateViewport,
+      }),
+      ViewportDimension({
+        viewport,
+        onResizeViewport,
       })
     );
   },
diff --git a/devtools/client/responsive.html/constants.js b/devtools/client/responsive.html/constants.js
new file mode 100644
index 000000000000..b848515ea2c5
--- /dev/null
+++ b/devtools/client/responsive.html/constants.js
@@ -0,0 +1,8 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// The minimum viewport width and height
+exports.MIN_VIEWPORT_DIMENSION = 280;
diff --git a/devtools/client/responsive.html/index.css b/devtools/client/responsive.html/index.css
index 1f7aa4841e4e..7e78f734a6d5 100644
--- a/devtools/client/responsive.html/index.css
+++ b/devtools/client/responsive.html/index.css
@@ -7,10 +7,14 @@
 
 .theme-light {
   --viewport-box-shadow: 0 4px 4px 0 rgba(155, 155, 155, 0.26);
+  --viewport-dimension-color: var(--theme-splitter-color);
+  --viewport-dimension-editing-color: var(--theme-body-color);
 }
 
 .theme-dark {
   --viewport-box-shadow: 0 4px 4px 0 rgba(105, 105, 105, 0.26);
+  --viewport-dimension-color: var(--theme-body-color);
+  --viewport-dimension-editing-color: var(--theme-selection-color);
 }
 
 * {
@@ -57,11 +61,11 @@ body {
   display: inline-block;
   /* Align all viewports to the top */
   vertical-align: top;
-  border: 1px solid var(--theme-splitter-color);
-  box-shadow: var(--viewport-box-shadow);
 }
 
 .resizable-viewport {
+  border: 1px solid var(--theme-splitter-color);
+  box-shadow: var(--viewport-box-shadow);
   position: relative;
 }
 
@@ -152,3 +156,47 @@ body {
   bottom: -4px;
   cursor: s-resize;
 }
+
+/**
+ * Viewport Dimension Label
+ */
+
+.viewport-dimension {
+  display: flex;
+  justify-content: center;
+  font: 10px sans-serif;
+  margin-top: 10px;
+}
+
+.viewport-dimension-editable {
+  border-bottom: 1px solid transparent;
+}
+
+.viewport-dimension-editable,
+.viewport-dimension-input {
+  color: var(--viewport-dimension-color);
+  transition: all 0.25s ease;
+}
+
+.viewport-dimension-editable.editing,
+.viewport-dimension-input.editing {
+  color: var(--viewport-dimension-editing-color);
+}
+
+.viewport-dimension-editable.editing {
+  border-bottom: 1px solid var(--theme-selection-background);
+}
+
+.viewport-dimension-editable.editing.invalid {
+  border-bottom: 1px solid #d92215;
+}
+
+.viewport-dimension-input {
+  background: transparent;
+  border: none;
+  text-align: center;
+}
+
+.viewport-dimension-separator {
+  -moz-user-select: none;
+}
diff --git a/devtools/client/responsive.html/moz.build b/devtools/client/responsive.html/moz.build
index 4fd8bafb29f0..5f0652a19a4b 100644
--- a/devtools/client/responsive.html/moz.build
+++ b/devtools/client/responsive.html/moz.build
@@ -13,6 +13,7 @@ DIRS += [
 
 DevToolsModules(
     'app.js',
+    'constants.js',
     'index.css',
     'manager.js',
     'reducers.js',
diff --git a/devtools/client/shared/telemetry.js b/devtools/client/shared/telemetry.js
index 2063347b5802..72cc5fb0471e 100644
--- a/devtools/client/shared/telemetry.js
+++ b/devtools/client/shared/telemetry.js
@@ -7,14 +7,14 @@
  *
  * To add metrics for a tool:
  *
- * 1. Create boolean, flag and exponential entries in
+ * 1. Create count, flag, and exponential entries in
  *    toolkit/components/telemetry/Histograms.json. Each type is optional but it
  *    is best if all three can be included.
  *
  * 2. Add your chart entries to devtools/client/shared/telemetry.js
  *    (Telemetry.prototype._histograms):
  *    mytoolname: {
- *      histogram: "DEVTOOLS_MYTOOLNAME_OPENED_BOOLEAN",
+ *      histogram: "DEVTOOLS_MYTOOLNAME_OPENED_COUNT",
  *      userHistogram: "DEVTOOLS_MYTOOLNAME_OPENED_PER_USER_FLAG",
  *      timerHistogram: "DEVTOOLS_MYTOOLNAME_TIME_ACTIVE_SECONDS"
  *    },
@@ -61,176 +61,176 @@ var {XPCOMUtils} = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
 Telemetry.prototype = {
   _histograms: {
     toolbox: {
-      histogram: "DEVTOOLS_TOOLBOX_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_TOOLBOX_OPENED_COUNT",
       userHistogram: "DEVTOOLS_TOOLBOX_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_TOOLBOX_TIME_ACTIVE_SECONDS"
     },
     options: {
-      histogram: "DEVTOOLS_OPTIONS_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_OPTIONS_OPENED_COUNT",
       userHistogram: "DEVTOOLS_OPTIONS_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_OPTIONS_TIME_ACTIVE_SECONDS"
     },
     webconsole: {
-      histogram: "DEVTOOLS_WEBCONSOLE_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_WEBCONSOLE_OPENED_COUNT",
       userHistogram: "DEVTOOLS_WEBCONSOLE_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_WEBCONSOLE_TIME_ACTIVE_SECONDS"
     },
     browserconsole: {
-      histogram: "DEVTOOLS_BROWSERCONSOLE_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_BROWSERCONSOLE_OPENED_COUNT",
       userHistogram: "DEVTOOLS_BROWSERCONSOLE_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_BROWSERCONSOLE_TIME_ACTIVE_SECONDS"
     },
     inspector: {
-      histogram: "DEVTOOLS_INSPECTOR_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_INSPECTOR_OPENED_COUNT",
       userHistogram: "DEVTOOLS_INSPECTOR_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_INSPECTOR_TIME_ACTIVE_SECONDS"
     },
     ruleview: {
-      histogram: "DEVTOOLS_RULEVIEW_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_RULEVIEW_OPENED_COUNT",
       userHistogram: "DEVTOOLS_RULEVIEW_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_RULEVIEW_TIME_ACTIVE_SECONDS"
     },
     computedview: {
-      histogram: "DEVTOOLS_COMPUTEDVIEW_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_COMPUTEDVIEW_OPENED_COUNT",
       userHistogram: "DEVTOOLS_COMPUTEDVIEW_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_COMPUTEDVIEW_TIME_ACTIVE_SECONDS"
     },
     layoutview: {
-      histogram: "DEVTOOLS_LAYOUTVIEW_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_LAYOUTVIEW_OPENED_COUNT",
       userHistogram: "DEVTOOLS_LAYOUTVIEW_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_LAYOUTVIEW_TIME_ACTIVE_SECONDS"
     },
     fontinspector: {
-      histogram: "DEVTOOLS_FONTINSPECTOR_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_FONTINSPECTOR_OPENED_COUNT",
       userHistogram: "DEVTOOLS_FONTINSPECTOR_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_FONTINSPECTOR_TIME_ACTIVE_SECONDS"
     },
     animationinspector: {
-      histogram: "DEVTOOLS_ANIMATIONINSPECTOR_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_ANIMATIONINSPECTOR_OPENED_COUNT",
       userHistogram: "DEVTOOLS_ANIMATIONINSPECTOR_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_ANIMATIONINSPECTOR_TIME_ACTIVE_SECONDS"
     },
     jsdebugger: {
-      histogram: "DEVTOOLS_JSDEBUGGER_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_JSDEBUGGER_OPENED_COUNT",
       userHistogram: "DEVTOOLS_JSDEBUGGER_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_JSDEBUGGER_TIME_ACTIVE_SECONDS"
     },
     jsbrowserdebugger: {
-      histogram: "DEVTOOLS_JSBROWSERDEBUGGER_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_JSBROWSERDEBUGGER_OPENED_COUNT",
       userHistogram: "DEVTOOLS_JSBROWSERDEBUGGER_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_JSBROWSERDEBUGGER_TIME_ACTIVE_SECONDS"
     },
     styleeditor: {
-      histogram: "DEVTOOLS_STYLEEDITOR_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_STYLEEDITOR_OPENED_COUNT",
       userHistogram: "DEVTOOLS_STYLEEDITOR_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_STYLEEDITOR_TIME_ACTIVE_SECONDS"
     },
     shadereditor: {
-      histogram: "DEVTOOLS_SHADEREDITOR_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_SHADEREDITOR_OPENED_COUNT",
       userHistogram: "DEVTOOLS_SHADEREDITOR_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_SHADEREDITOR_TIME_ACTIVE_SECONDS"
     },
     webaudioeditor: {
-      histogram: "DEVTOOLS_WEBAUDIOEDITOR_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_WEBAUDIOEDITOR_OPENED_COUNT",
       userHistogram: "DEVTOOLS_WEBAUDIOEDITOR_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_WEBAUDIOEDITOR_TIME_ACTIVE_SECONDS"
     },
     canvasdebugger: {
-      histogram: "DEVTOOLS_CANVASDEBUGGER_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_CANVASDEBUGGER_OPENED_COUNT",
       userHistogram: "DEVTOOLS_CANVASDEBUGGER_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_CANVASDEBUGGER_TIME_ACTIVE_SECONDS"
     },
     performance: {
-      histogram: "DEVTOOLS_JSPROFILER_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_JSPROFILER_OPENED_COUNT",
       userHistogram: "DEVTOOLS_JSPROFILER_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_JSPROFILER_TIME_ACTIVE_SECONDS"
     },
     memory: {
-      histogram: "DEVTOOLS_MEMORY_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_MEMORY_OPENED_COUNT",
       userHistogram: "DEVTOOLS_MEMORY_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_MEMORY_TIME_ACTIVE_SECONDS"
     },
     netmonitor: {
-      histogram: "DEVTOOLS_NETMONITOR_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_NETMONITOR_OPENED_COUNT",
       userHistogram: "DEVTOOLS_NETMONITOR_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_NETMONITOR_TIME_ACTIVE_SECONDS"
     },
     storage: {
-      histogram: "DEVTOOLS_STORAGE_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_STORAGE_OPENED_COUNT",
       userHistogram: "DEVTOOLS_STORAGE_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_STORAGE_TIME_ACTIVE_SECONDS"
     },
     tilt: {
-      histogram: "DEVTOOLS_TILT_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_TILT_OPENED_COUNT",
       userHistogram: "DEVTOOLS_TILT_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_TILT_TIME_ACTIVE_SECONDS"
     },
     paintflashing: {
-      histogram: "DEVTOOLS_PAINTFLASHING_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_PAINTFLASHING_OPENED_COUNT",
       userHistogram: "DEVTOOLS_PAINTFLASHING_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_PAINTFLASHING_TIME_ACTIVE_SECONDS"
     },
     scratchpad: {
-      histogram: "DEVTOOLS_SCRATCHPAD_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_SCRATCHPAD_OPENED_COUNT",
       userHistogram: "DEVTOOLS_SCRATCHPAD_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_SCRATCHPAD_TIME_ACTIVE_SECONDS"
     },
     "scratchpad-window": {
-      histogram: "DEVTOOLS_SCRATCHPAD_WINDOW_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_SCRATCHPAD_WINDOW_OPENED_COUNT",
       userHistogram: "DEVTOOLS_SCRATCHPAD_WINDOW_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_SCRATCHPAD_WINDOW_TIME_ACTIVE_SECONDS"
     },
     responsive: {
-      histogram: "DEVTOOLS_RESPONSIVE_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_RESPONSIVE_OPENED_COUNT",
       userHistogram: "DEVTOOLS_RESPONSIVE_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_RESPONSIVE_TIME_ACTIVE_SECONDS"
     },
     eyedropper: {
-      histogram: "DEVTOOLS_EYEDROPPER_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_EYEDROPPER_OPENED_COUNT",
       userHistogram: "DEVTOOLS_EYEDROPPER_OPENED_PER_USER_FLAG",
     },
     menueyedropper: {
-      histogram: "DEVTOOLS_MENU_EYEDROPPER_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_MENU_EYEDROPPER_OPENED_COUNT",
       userHistogram: "DEVTOOLS_MENU_EYEDROPPER_OPENED_PER_USER_FLAG",
     },
     pickereyedropper: {
-      histogram: "DEVTOOLS_PICKER_EYEDROPPER_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_PICKER_EYEDROPPER_OPENED_COUNT",
       userHistogram: "DEVTOOLS_PICKER_EYEDROPPER_OPENED_PER_USER_FLAG",
     },
     developertoolbar: {
-      histogram: "DEVTOOLS_DEVELOPERTOOLBAR_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_DEVELOPERTOOLBAR_OPENED_COUNT",
       userHistogram: "DEVTOOLS_DEVELOPERTOOLBAR_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_DEVELOPERTOOLBAR_TIME_ACTIVE_SECONDS"
     },
     aboutdebugging: {
-      histogram: "DEVTOOLS_ABOUTDEBUGGING_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_ABOUTDEBUGGING_OPENED_COUNT",
       userHistogram: "DEVTOOLS_ABOUTDEBUGGING_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_ABOUTDEBUGGING_TIME_ACTIVE_SECONDS"
     },
     webide: {
-      histogram: "DEVTOOLS_WEBIDE_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_WEBIDE_OPENED_COUNT",
       userHistogram: "DEVTOOLS_WEBIDE_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_WEBIDE_TIME_ACTIVE_SECONDS"
     },
     webideProjectEditor: {
-      histogram: "DEVTOOLS_WEBIDE_PROJECT_EDITOR_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_WEBIDE_PROJECT_EDITOR_OPENED_COUNT",
       userHistogram: "DEVTOOLS_WEBIDE_PROJECT_EDITOR_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_WEBIDE_PROJECT_EDITOR_TIME_ACTIVE_SECONDS"
     },
     webideProjectEditorSave: {
-      histogram: "DEVTOOLS_WEBIDE_PROJECT_EDITOR_SAVE_BOOLEAN",
+      histogram: "DEVTOOLS_WEBIDE_PROJECT_EDITOR_SAVE_COUNT",
       userHistogram: "DEVTOOLS_WEBIDE_PROJECT_EDITOR_SAVE_PER_USER_FLAG",
     },
     webideNewProject: {
-      histogram: "DEVTOOLS_WEBIDE_NEW_PROJECT_BOOLEAN",
+      histogram: "DEVTOOLS_WEBIDE_NEW_PROJECT_COUNT",
       userHistogram: "DEVTOOLS_WEBIDE_NEW_PROJECT_PER_USER_FLAG",
     },
     webideImportProject: {
-      histogram: "DEVTOOLS_WEBIDE_IMPORT_PROJECT_BOOLEAN",
+      histogram: "DEVTOOLS_WEBIDE_IMPORT_PROJECT_COUNT",
       userHistogram: "DEVTOOLS_WEBIDE_IMPORT_PROJECT_PER_USER_FLAG",
     },
     custom: {
-      histogram: "DEVTOOLS_CUSTOM_OPENED_BOOLEAN",
+      histogram: "DEVTOOLS_CUSTOM_OPENED_COUNT",
       userHistogram: "DEVTOOLS_CUSTOM_OPENED_PER_USER_FLAG",
       timerHistogram: "DEVTOOLS_CUSTOM_TIME_ACTIVE_SECONDS"
     }
diff --git a/devtools/client/shared/test/browser_telemetry_button_eyedropper.js b/devtools/client/shared/test/browser_telemetry_button_eyedropper.js
index 0ff8260b5201..14ad9ef91a0b 100644
--- a/devtools/client/shared/test/browser_telemetry_button_eyedropper.js
+++ b/devtools/client/shared/test/browser_telemetry_button_eyedropper.js
@@ -51,7 +51,7 @@ function checkResults(histIdFocus, Telemetry) {
     if (histId.endsWith("OPENED_PER_USER_FLAG")) {
       ok(value.length === 1 && value[0] === true,
          "Per user value " + histId + " has a single value of true");
-    } else if (histId.endsWith("OPENED_BOOLEAN")) {
+    } else if (histId.endsWith("OPENED_COUNT")) {
       is(value.length, 1, histId + " has one entry");
 
       let okay = value.every(element => element === true);
diff --git a/devtools/client/shared/test/browser_telemetry_button_paintflashing.js b/devtools/client/shared/test/browser_telemetry_button_paintflashing.js
index e402029a30f8..f910655af502 100644
--- a/devtools/client/shared/test/browser_telemetry_button_paintflashing.js
+++ b/devtools/client/shared/test/browser_telemetry_button_paintflashing.js
@@ -71,7 +71,7 @@ function checkResults(histIdFocus, Telemetry) {
     if (histId.endsWith("OPENED_PER_USER_FLAG")) {
       ok(value.length === 1 && value[0] === true,
          "Per user value " + histId + " has a single value of true");
-    } else if (histId.endsWith("OPENED_BOOLEAN")) {
+    } else if (histId.endsWith("OPENED_COUNT")) {
       ok(value.length > 1, histId + " has more than one entry");
 
       let okay = value.every(function(element) {
diff --git a/devtools/client/shared/test/browser_telemetry_button_responsive.js b/devtools/client/shared/test/browser_telemetry_button_responsive.js
index f88eb47f2ba7..3227e7ed6892 100644
--- a/devtools/client/shared/test/browser_telemetry_button_responsive.js
+++ b/devtools/client/shared/test/browser_telemetry_button_responsive.js
@@ -74,7 +74,7 @@ function checkResults(histIdFocus, Telemetry) {
     if (histId.endsWith("OPENED_PER_USER_FLAG")) {
       ok(value.length === 1 && value[0] === true,
          "Per user value " + histId + " has a single value of true");
-    } else if (histId.endsWith("OPENED_BOOLEAN")) {
+    } else if (histId.endsWith("OPENED_COUNT")) {
       ok(value.length > 1, histId + " has more than one entry");
 
       let okay = value.every(function(element) {
diff --git a/devtools/client/shared/test/browser_telemetry_button_scratchpad.js b/devtools/client/shared/test/browser_telemetry_button_scratchpad.js
index 39431b9112a0..cf1bdf3458df 100644
--- a/devtools/client/shared/test/browser_telemetry_button_scratchpad.js
+++ b/devtools/client/shared/test/browser_telemetry_button_scratchpad.js
@@ -106,7 +106,7 @@ function checkResults(histIdFocus, Telemetry) {
     if (histId.endsWith("OPENED_PER_USER_FLAG")) {
       ok(value.length === 1 && value[0] === true,
          "Per user value " + histId + " has a single value of true");
-    } else if (histId.endsWith("OPENED_BOOLEAN")) {
+    } else if (histId.endsWith("OPENED_COUNT")) {
       ok(value.length > 1, histId + " has more than one entry");
 
       let okay = value.every(function(element) {
diff --git a/devtools/client/shared/test/browser_telemetry_button_tilt.js b/devtools/client/shared/test/browser_telemetry_button_tilt.js
index 386cef5e8b62..743ac5e97b71 100644
--- a/devtools/client/shared/test/browser_telemetry_button_tilt.js
+++ b/devtools/client/shared/test/browser_telemetry_button_tilt.js
@@ -89,7 +89,7 @@ function checkResults(histIdFocus, Telemetry) {
     if (histId.endsWith("OPENED_PER_USER_FLAG")) {
       ok(value.length === 1 && value[0] === true,
          "Per user value " + histId + " has a single value of true");
-    } else if (histId.endsWith("OPENED_BOOLEAN")) {
+    } else if (histId.endsWith("OPENED_COUNT")) {
       ok(value.length > 1, histId + " has more than one entry");
 
       let okay = value.every(function(element) {
diff --git a/devtools/client/shared/test/browser_telemetry_sidebar.js b/devtools/client/shared/test/browser_telemetry_sidebar.js
index c088837ae454..8582d2dc677c 100644
--- a/devtools/client/shared/test/browser_telemetry_sidebar.js
+++ b/devtools/client/shared/test/browser_telemetry_sidebar.js
@@ -62,9 +62,9 @@ function checkResults(Telemetry) {
     if (histId.endsWith("OPENED_PER_USER_FLAG")) {
       ok(value.length === 1 && value[0] === true,
          "Per user value " + histId + " has a single value of true");
-    } else if (histId === "DEVTOOLS_TOOLBOX_OPENED_BOOLEAN") {
+    } else if (histId === "DEVTOOLS_TOOLBOX_OPENED_COUNT") {
       is(value.length, 1, histId + " has only one entry");
-    } else if (histId.endsWith("OPENED_BOOLEAN")) {
+    } else if (histId.endsWith("OPENED_COUNT")) {
       ok(value.length > 1, histId + " has more than one entry");
 
       let okay = value.every(function(element) {
diff --git a/devtools/client/shared/test/head.js b/devtools/client/shared/test/head.js
index 19c06f3ba04a..3356863bcbcf 100644
--- a/devtools/client/shared/test/head.js
+++ b/devtools/client/shared/test/head.js
@@ -168,7 +168,7 @@ function checkTelemetryResults(Telemetry) {
     if (histId.endsWith("OPENED_PER_USER_FLAG")) {
       ok(value.length === 1 && value[0] === true,
          "Per user value " + histId + " has a single value of true");
-    } else if (histId.endsWith("OPENED_BOOLEAN")) {
+    } else if (histId.endsWith("OPENED_COUNT")) {
       ok(value.length > 1, histId + " has more than one entry");
 
       let okay = value.every(function(element) {
diff --git a/devtools/client/webide/test/test_telemetry.html b/devtools/client/webide/test/test_telemetry.html
index bc118d1a5686..840336861410 100644
--- a/devtools/client/webide/test/test_telemetry.html
+++ b/devtools/client/webide/test/test_telemetry.html
@@ -172,10 +172,10 @@
             ok(value.length === 1 && !!value[0],
                histId + " has 1 successful entry");
           } else if (histId ===
-                     "DEVTOOLS_WEBIDE_PROJECT_EDITOR_OPENED_BOOLEAN") {
+                     "DEVTOOLS_WEBIDE_PROJECT_EDITOR_OPENED_COUNT") {
             ok(value.length === 1 && !!value[0],
                histId + " has 1 successful entry");
-          } else if (histId === "DEVTOOLS_WEBIDE_OPENED_BOOLEAN") {
+          } else if (histId === "DEVTOOLS_WEBIDE_OPENED_COUNT") {
             ok(value.length > 1, histId + " has more than one entry");
 
             let okay = value.every(function(element) {
diff --git a/dom/bindings/Codegen.py b/dom/bindings/Codegen.py
index 1720ce228ea7..31099628e32e 100644
--- a/dom/bindings/Codegen.py
+++ b/dom/bindings/Codegen.py
@@ -12826,6 +12826,46 @@ class CGRegisterWorkerBindings(CGAbstractMethod):
         lines.append(CGGeneric("return true;\n"))
         return CGList(lines, "\n").define()
 
+class CGRegisterWorkerDebuggerBindings(CGAbstractMethod):
+    def __init__(self, config):
+        CGAbstractMethod.__init__(self, None, 'RegisterWorkerDebuggerBindings', 'bool',
+                                  [Argument('JSContext*', 'aCx'),
+                                   Argument('JS::Handle<JSObject*>', 'aObj')])
+        self.config = config
+
+    def definition_body(self):
+        # We have to be a bit careful: Some of the interfaces we want to expose
+        # in workers only have one descriptor, while others have both a worker
+        # and a non-worker descriptor.  When both are present we want the worker
+        # descriptor, but otherwise we want whatever descriptor we've got.
+        descriptors = self.config.getDescriptors(hasInterfaceObject=True,
+                                                 isExposedInWorkerDebugger=True,
+                                                 register=True,
+                                                 skipGen=False,
+                                                 workers=True)
+        workerDescriptorIfaceNames = set(d.interface.identifier.name for
+                                         d in descriptors)
+        descriptors.extend(
+            filter(
+                lambda d: d.interface.identifier.name not in workerDescriptorIfaceNames,
+                self.config.getDescriptors(hasInterfaceObject=True,
+                                           isExposedInWorkerDebugger=True,
+                                           register=True,
+                                           skipGen=False,
+                                           workers=False)))
+        conditions = []
+        for desc in descriptors:
+            bindingNS = toBindingNamespace(desc.name)
+            condition = "!%s::GetConstructorObject(aCx, aObj)" % bindingNS
+            if desc.isExposedConditionally():
+                condition = (
+                    "%s::ConstructorEnabled(aCx, aObj) && " % bindingNS
+                    + condition)
+            conditions.append(condition)
+        lines = [CGIfWrapper(CGGeneric("return false;\n"), condition) for
+                 condition in conditions]
+        lines.append(CGGeneric("return true;\n"))
+        return CGList(lines, "\n").define()
 
 class CGResolveSystemBinding(CGAbstractMethod):
     def __init__(self, config):
@@ -16081,6 +16121,32 @@ class GlobalGenRoots():
         # Done.
         return curr
 
+    @staticmethod
+    def RegisterWorkerDebuggerBindings(config):
+
+        curr = CGRegisterWorkerDebuggerBindings(config)
+
+        # Wrap all of that in our namespaces.
+        curr = CGNamespace.build(['mozilla', 'dom'],
+                                 CGWrapper(curr, post='\n'))
+        curr = CGWrapper(curr, post='\n')
+
+        # Add the includes
+        defineIncludes = [CGHeaders.getDeclarationFilename(desc.interface)
+                          for desc in config.getDescriptors(hasInterfaceObject=True,
+                                                            register=True,
+                                                            isExposedInWorkerDebugger=True,
+                                                            skipGen=False)]
+
+        curr = CGHeaders([], [], [], [], [], defineIncludes,
+                         'RegisterWorkerDebuggerBindings', curr)
+
+        # Add include guards.
+        curr = CGIncludeGuard('RegisterWorkerDebuggerBindings', curr)
+
+        # Done.
+        return curr
+
     @staticmethod
     def ResolveSystemBinding(config):
 
diff --git a/dom/bindings/Configuration.py b/dom/bindings/Configuration.py
index 21c1dd6b6fbe..222a239efa7e 100644
--- a/dom/bindings/Configuration.py
+++ b/dom/bindings/Configuration.py
@@ -228,6 +228,8 @@ class Configuration:
                 getter = lambda x: x.interface.getNavigatorProperty() is not None
             elif key == 'isExposedInAnyWorker':
                 getter = lambda x: x.interface.isExposedInAnyWorker()
+            elif key == 'isExposedInWorkerDebugger':
+                getter = lambda x: x.interface.isExposedInWorkerDebugger()
             elif key == 'isExposedInSystemGlobals':
                 getter = lambda x: x.interface.isExposedInSystemGlobals()
             elif key == 'isExposedInWindow':
diff --git a/dom/bindings/mozwebidlcodegen/__init__.py b/dom/bindings/mozwebidlcodegen/__init__.py
index d79ed44bbe06..6a2f52aa69de 100644
--- a/dom/bindings/mozwebidlcodegen/__init__.py
+++ b/dom/bindings/mozwebidlcodegen/__init__.py
@@ -133,6 +133,7 @@ class WebIDLCodegenManager(LoggingMixin):
         'PrototypeList.h',
         'RegisterBindings.h',
         'RegisterWorkerBindings.h',
+        'RegisterWorkerDebuggerBindings.h',
         'ResolveSystemBinding.h',
         'UnionConversions.h',
         'UnionTypes.h',
@@ -142,6 +143,7 @@ class WebIDLCodegenManager(LoggingMixin):
     GLOBAL_DEFINE_FILES = {
         'RegisterBindings.cpp',
         'RegisterWorkerBindings.cpp',
+        'RegisterWorkerDebuggerBindings.cpp',
         'ResolveSystemBinding.cpp',
         'UnionTypes.cpp',
         'PrototypeList.cpp',
diff --git a/dom/bindings/parser/WebIDL.py b/dom/bindings/parser/WebIDL.py
index 9d7e98ce31de..062701b51abf 100644
--- a/dom/bindings/parser/WebIDL.py
+++ b/dom/bindings/parser/WebIDL.py
@@ -508,6 +508,9 @@ class IDLExposureMixins():
     def isExposedInAnyWorker(self):
         return len(self.getWorkerExposureSet()) > 0
 
+    def isExposedInWorkerDebugger(self):
+        return len(self.getWorkerDebuggerExposureSet()) > 0
+
     def isExposedInSystemGlobals(self):
         return 'BackstagePass' in self.exposureSet
 
@@ -527,6 +530,10 @@ class IDLExposureMixins():
         workerScopes = self._globalScope.globalNameMapping["Worker"]
         return workerScopes.intersection(self.exposureSet)
 
+    def getWorkerDebuggerExposureSet(self):
+        workerDebuggerScopes = self._globalScope.globalNameMapping["WorkerDebugger"]
+        return workerDebuggerScopes.intersection(self.exposureSet)
+
 
 class IDLExternalInterface(IDLObjectWithIdentifier, IDLExposureMixins):
     def __init__(self, location, parentScope, identifier):
diff --git a/dom/webidl/URL.webidl b/dom/webidl/URL.webidl
index fd577885dc89..055cb2dc7d53 100644
--- a/dom/webidl/URL.webidl
+++ b/dom/webidl/URL.webidl
@@ -15,7 +15,7 @@
 // [Constructor(DOMString url, optional (URL or DOMString) base = "about:blank")]
 [Constructor(DOMString url, URL base),
  Constructor(DOMString url, optional DOMString base),
- Exposed=(Window,Worker)]
+ Exposed=(Window,Worker,WorkerDebugger)]
 interface URL {
   // Bug 824857: no support for stringifier attributes yet.
   //  stringifier attribute USVString href;
diff --git a/dom/webidl/URLSearchParams.webidl b/dom/webidl/URLSearchParams.webidl
index a5ef263895b2..93e846071936 100644
--- a/dom/webidl/URLSearchParams.webidl
+++ b/dom/webidl/URLSearchParams.webidl
@@ -15,7 +15,7 @@
 
 [Constructor(optional USVString init = ""),
  Constructor(URLSearchParams init),
- Exposed=(Window,Worker,System)]
+ Exposed=(Window,Worker,WorkerDebugger,System)]
 interface URLSearchParams {
   void append(USVString name, USVString value);
   void delete(USVString name);
diff --git a/dom/workers/RegisterBindings.cpp b/dom/workers/RegisterBindings.cpp
index 04c8c457c513..b6c1e9cfd4fd 100644
--- a/dom/workers/RegisterBindings.cpp
+++ b/dom/workers/RegisterBindings.cpp
@@ -10,6 +10,7 @@
 
 #include "jsapi.h"
 #include "mozilla/dom/RegisterWorkerBindings.h"
+#include "mozilla/dom/RegisterWorkerDebuggerBindings.h"
 #include "mozilla/OSFileConstants.h"
 
 USING_WORKERS_NAMESPACE
@@ -36,3 +37,19 @@ WorkerPrivate::RegisterBindings(JSContext* aCx, JS::Handle<JSObject*> aGlobal)
 
   return true;
 }
+
+bool
+WorkerPrivate::RegisterDebuggerBindings(JSContext* aCx,
+                                        JS::Handle<JSObject*> aGlobal)
+{
+  // Init Web IDL bindings
+  if (!RegisterWorkerDebuggerBindings(aCx, aGlobal)) {
+    return false;
+  }
+
+  if (!JS_DefineDebuggerObject(aCx, aGlobal)) {
+    return false;
+  }
+
+  return true;
+}
diff --git a/dom/workers/WorkerPrivate.cpp b/dom/workers/WorkerPrivate.cpp
index 151c52706941..44c5fe06f5c0 100644
--- a/dom/workers/WorkerPrivate.cpp
+++ b/dom/workers/WorkerPrivate.cpp
@@ -6440,14 +6440,18 @@ WorkerPrivate::CreateDebuggerGlobalScope(JSContext* aCx)
 
   JSAutoCompartment ac(aCx, global);
 
-  if (!JS_DefineDebuggerObject(aCx, global)) {
+  // RegisterDebuggerBindings() can spin a nested event loop so we have to set
+  // mDebuggerScope before calling it, and we have to make sure to unset
+  // mDebuggerScope if it fails.
+  mDebuggerScope = Move(globalScope);
+
+  if (!RegisterDebuggerBindings(aCx, global)) {
+    mDebuggerScope = nullptr;
     return nullptr;
   }
 
   JS_FireOnNewGlobalObject(aCx, global);
 
-  mDebuggerScope = globalScope.forget();
-
   return mDebuggerScope;
 }
 
diff --git a/dom/workers/WorkerPrivate.h b/dom/workers/WorkerPrivate.h
index 9dc835151ce8..54613fd7898d 100644
--- a/dom/workers/WorkerPrivate.h
+++ b/dom/workers/WorkerPrivate.h
@@ -1264,6 +1264,9 @@ public:
   bool
   RegisterBindings(JSContext* aCx, JS::Handle<JSObject*> aGlobal);
 
+  bool
+  RegisterDebuggerBindings(JSContext* aCx, JS::Handle<JSObject*> aGlobal);
+
 #define WORKER_SIMPLE_PREF(name, getter, NAME)                                \
   bool                                                                        \
   getter() const                                                              \
diff --git a/mobile/android/base/AppConstants.java.in b/mobile/android/base/AppConstants.java.in
index 5fe577c95648..3e8adc25e2ec 100644
--- a/mobile/android/base/AppConstants.java.in
+++ b/mobile/android/base/AppConstants.java.in
@@ -24,8 +24,7 @@ public class AppConstants {
     public static final String ANDROID_PACKAGE_NAME = "@ANDROID_PACKAGE_NAME@";
     public static final String MANGLED_ANDROID_PACKAGE_NAME = "@MANGLED_ANDROID_PACKAGE_NAME@";
 
-    public static final String MOZ_ANDROID_SHARED_ACCOUNT_TYPE = "@MOZ_ANDROID_SHARED_ACCOUNT_TYPE@";
-    public static final String MOZ_ANDROID_SHARED_FXACCOUNT_TYPE = "@MOZ_ANDROID_SHARED_FXACCOUNT_TYPE@";
+    public static final String MOZ_ANDROID_SHARED_FXACCOUNT_TYPE = "@ANDROID_PACKAGE_NAME@_fxaccount";
 
     /**
      * Encapsulates access to compile-time version definitions, allowing
diff --git a/mobile/android/base/Makefile.in b/mobile/android/base/Makefile.in
index 3b5d3a2cf3aa..2baf77b692cb 100644
--- a/mobile/android/base/Makefile.in
+++ b/mobile/android/base/Makefile.in
@@ -27,8 +27,6 @@ endif
 DEFINES += \
   -DANDROID_VERSION_CODE=$(ANDROID_VERSION_CODE) \
   -DMOZ_ANDROID_SHARED_ID="$(MOZ_ANDROID_SHARED_ID)" \
-  -DMOZ_ANDROID_SHARED_ACCOUNT_TYPE="$(MOZ_ANDROID_SHARED_ACCOUNT_TYPE)" \
-  -DMOZ_ANDROID_SHARED_FXACCOUNT_TYPE="$(MOZ_ANDROID_SHARED_FXACCOUNT_TYPE)" \
   -DMOZ_BUILDID=$(MOZ_BUILDID) \
   $(NULL)
 
diff --git a/mobile/android/base/locales/Makefile.in b/mobile/android/base/locales/Makefile.in
index a1352e22c6fb..ce0636c12609 100644
--- a/mobile/android/base/locales/Makefile.in
+++ b/mobile/android/base/locales/Makefile.in
@@ -60,17 +60,12 @@ strings-xml-preqs =\
   $(if $(IS_LANGUAGE_REPACK),FORCE) \
   $(NULL)
 
-$(if $(MOZ_ANDROID_SHARED_ACCOUNT_TYPE),,$(error Missing MOZ_ANDROID_SHARED_ACCOUNT_TYPE))
-$(if $(MOZ_ANDROID_SHARED_FXACCOUNT_TYPE),,$(error Missing MOZ_ANDROID_SHARED_FXACCOUNT_TYPE))
-
 $(dir-strings-xml)/strings.xml: $(strings-xml-preqs)
 	$(call py_action,preprocessor, \
       $(DEFINES) \
       $(ACDEFINES) \
 	  -DANDROID_PACKAGE_NAME=$(ANDROID_PACKAGE_NAME) \
 	  -DBRANDPATH='$(BRANDPATH)' \
-	  -DMOZ_ANDROID_SHARED_ACCOUNT_TYPE=$(MOZ_ANDROID_SHARED_ACCOUNT_TYPE) \
-	  -DMOZ_ANDROID_SHARED_FXACCOUNT_TYPE=$(MOZ_ANDROID_SHARED_FXACCOUNT_TYPE) \
 	  -DMOZ_APP_DISPLAYNAME='@MOZ_APP_DISPLAYNAME@' \
 	  -DSTRINGSPATH='$(STRINGSPATH)' \
 	  -DSYNCSTRINGSPATH='$(SYNCSTRINGSPATH)' \
diff --git a/mobile/android/base/strings.xml.in b/mobile/android/base/strings.xml.in
index 32272efa6db4..26f18622ee51 100644
--- a/mobile/android/base/strings.xml.in
+++ b/mobile/android/base/strings.xml.in
@@ -27,8 +27,7 @@
   <string name="content_authority_db_passwords">@ANDROID_PACKAGE_NAME@.db.passwords</string>
   <string name="content_authority_db_tabs">@ANDROID_PACKAGE_NAME@.db.tabs</string>
   <string name="content_authority_db_readinglist">@ANDROID_PACKAGE_NAME@.db.readinglist</string>
-  <string name="moz_android_shared_account_type">@MOZ_ANDROID_SHARED_ACCOUNT_TYPE@</string>
-  <string name="moz_android_shared_fxaccount_type">@MOZ_ANDROID_SHARED_FXACCOUNT_TYPE@</string>
+  <string name="moz_android_shared_fxaccount_type">@ANDROID_PACKAGE_NAME@_fxaccount</string>
   <string name="android_package_name_for_ui">@ANDROID_PACKAGE_NAME@</string>
 
 #include ../search/strings/search_strings.xml.in
diff --git a/mobile/android/bouncer/Makefile.in b/mobile/android/bouncer/Makefile.in
index 058d70c25c5a..9ce1964ff33b 100644
--- a/mobile/android/bouncer/Makefile.in
+++ b/mobile/android/bouncer/Makefile.in
@@ -18,8 +18,6 @@ manifest_TARGET := export
 # Special 'cuz they are set in mobile/android/defs.mk.
 manifest_FLAGS += \
   -DMOZ_ANDROID_SHARED_ID="$(MOZ_ANDROID_SHARED_ID)" \
-  -DMOZ_ANDROID_SHARED_ACCOUNT_TYPE="$(MOZ_ANDROID_SHARED_ACCOUNT_TYPE)" \
-  -DMOZ_ANDROID_SHARED_FXACCOUNT_TYPE="$(MOZ_ANDROID_SHARED_FXACCOUNT_TYPE)" \
   $(NULL)
 
 # Targets built very early during a Gradle build.
diff --git a/mobile/android/branding/aurora/configure.sh b/mobile/android/branding/aurora/configure.sh
index ee33330a762b..fb5b3e4ba3e0 100644
--- a/mobile/android/branding/aurora/configure.sh
+++ b/mobile/android/branding/aurora/configure.sh
@@ -6,3 +6,4 @@ MOZ_APP_DISPLAYNAME=Aurora
 ANDROID_PACKAGE_NAME=org.mozilla.fennec_aurora
 MOZ_UPDATER=1
 MOZ_ANDROID_ANR_REPORTER=1
+MOZ_ANDROID_SHARED_ID=org.mozilla.fennec.sharedID
diff --git a/mobile/android/branding/beta/configure.sh b/mobile/android/branding/beta/configure.sh
index e914476edd46..8b12d4d37db4 100644
--- a/mobile/android/branding/beta/configure.sh
+++ b/mobile/android/branding/beta/configure.sh
@@ -6,3 +6,4 @@ MOZ_APP_DISPLAYNAME="Firefox Beta"
 ANDROID_PACKAGE_NAME=org.mozilla.firefox_beta
 MOZ_UPDATER=
 MOZ_ANDROID_ANR_REPORTER=
+MOZ_ANDROID_SHARED_ID=org.mozilla.firefox.sharedID
diff --git a/mobile/android/branding/nightly/configure.sh b/mobile/android/branding/nightly/configure.sh
index 95f2a36158ce..34b5e6f61345 100644
--- a/mobile/android/branding/nightly/configure.sh
+++ b/mobile/android/branding/nightly/configure.sh
@@ -5,3 +5,4 @@
 MOZ_APP_DISPLAYNAME=Nightly
 MOZ_UPDATER=1
 MOZ_ANDROID_ANR_REPORTER=1
+MOZ_ANDROID_SHARED_ID=org.mozilla.fennec.sharedID
diff --git a/mobile/android/branding/official/configure.sh b/mobile/android/branding/official/configure.sh
index 5626cddf6586..38da9fc9290e 100644
--- a/mobile/android/branding/official/configure.sh
+++ b/mobile/android/branding/official/configure.sh
@@ -6,3 +6,4 @@ MOZ_APP_DISPLAYNAME=Firefox
 ANDROID_PACKAGE_NAME=org.mozilla.firefox
 MOZ_UPDATER=
 MOZ_ANDROID_ANR_REPORTER=
+MOZ_ANDROID_SHARED_ID=org.mozilla.firefox.sharedID
diff --git a/mobile/android/components/SessionStore.js b/mobile/android/components/SessionStore.js
index 1d64faba3b28..c4ae1a61cd80 100644
--- a/mobile/android/components/SessionStore.js
+++ b/mobile/android/components/SessionStore.js
@@ -752,6 +752,10 @@ SessionStore.prototype = {
       entry.referrer = aEntry.referrerURI.spec;
     }
 
+    if (aEntry.originalURI) {
+      entry.originalURI = aEntry.originalURI.spec;
+    }
+
     if (aEntry.contentType) {
       entry.contentType = aEntry.contentType;
     }
@@ -836,6 +840,10 @@ SessionStore.prototype = {
       shEntry.referrerURI = Services.io.newURI(aEntry.referrer, null, null);
     }
 
+    if (aEntry.originalURI) {
+      shEntry.originalURI =  Services.io.newURI(aEntry.originalURI, null, null);
+    }
+
     if (aEntry.cacheKey) {
       let cacheKey = Cc["@mozilla.org/supports-PRUint32;1"].createInstance(Ci.nsISupportsPRUint32);
       cacheKey.data = aEntry.cacheKey;
diff --git a/mobile/android/defs.mk b/mobile/android/defs.mk
deleted file mode 100644
index 6c9e94921bde..000000000000
--- a/mobile/android/defs.mk
+++ /dev/null
@@ -1,22 +0,0 @@
-MOZ_ANDROID_SHARED_ID = $(ANDROID_PACKAGE_NAME).sharedID
-# Android Sync Account types are not per-package: release and beta
-# share an Account type, and aurora and nightly share an Account type.
-MOZ_ANDROID_SHARED_ACCOUNT_TYPE = $(ANDROID_PACKAGE_NAME)_sync
-# Firefox Accounts Account types are per-package.
-MOZ_ANDROID_SHARED_FXACCOUNT_TYPE = $(ANDROID_PACKAGE_NAME)_fxaccount
-
-# We released these builds to the public with shared IDs and need to
-# keep them consistent.
-ifeq (org.mozilla.firefox,$(ANDROID_PACKAGE_NAME))
-MOZ_ANDROID_SHARED_ID = org.mozilla.firefox.sharedID
-MOZ_ANDROID_SHARED_ACCOUNT_TYPE = org.mozilla.firefox_sync
-else ifeq (org.mozilla.firefox_beta,$(ANDROID_PACKAGE_NAME))
-MOZ_ANDROID_SHARED_ID = org.mozilla.firefox.sharedID
-MOZ_ANDROID_SHARED_ACCOUNT_TYPE = org.mozilla.firefox_sync
-else ifeq (org.mozilla.fennec_aurora,$(ANDROID_PACKAGE_NAME))
-MOZ_ANDROID_SHARED_ID = org.mozilla.fennec.sharedID
-MOZ_ANDROID_SHARED_ACCOUNT_TYPE = org.mozilla.fennec_sync
-else ifeq (org.mozilla.fennec,$(ANDROID_PACKAGE_NAME))
-MOZ_ANDROID_SHARED_ID = org.mozilla.fennec.sharedID
-MOZ_ANDROID_SHARED_ACCOUNT_TYPE = org.mozilla.fennec_sync
-endif
diff --git a/mobile/android/services/manifests/FxAccountAndroidManifest_activities.xml.in b/mobile/android/services/manifests/FxAccountAndroidManifest_activities.xml.in
index 22f409dbf054..8b41be60435e 100644
--- a/mobile/android/services/manifests/FxAccountAndroidManifest_activities.xml.in
+++ b/mobile/android/services/manifests/FxAccountAndroidManifest_activities.xml.in
@@ -20,9 +20,9 @@
 
         <receiver
             android:name="org.mozilla.gecko.fxa.receivers.FxAccountDeletedReceiver"
-            android:permission="@MOZ_ANDROID_SHARED_FXACCOUNT_TYPE@.permission.PER_ACCOUNT_TYPE">
+            android:permission="@ANDROID_PACKAGE_NAME@_fxaccount.permission.PER_ACCOUNT_TYPE">
             <intent-filter>
-                <action android:name="@MOZ_ANDROID_SHARED_FXACCOUNT_TYPE@.accounts.ACCOUNT_DELETED_ACTION"/>
+                <action android:name="@ANDROID_PACKAGE_NAME@_fxaccount.accounts.ACCOUNT_DELETED_ACTION"/>
             </intent-filter>
         </receiver>
 
diff --git a/mobile/android/services/manifests/FxAccountAndroidManifest_permissions.xml.in b/mobile/android/services/manifests/FxAccountAndroidManifest_permissions.xml.in
index 9c530d3054f8..d5c7e3e5c7dc 100644
--- a/mobile/android/services/manifests/FxAccountAndroidManifest_permissions.xml.in
+++ b/mobile/android/services/manifests/FxAccountAndroidManifest_permissions.xml.in
@@ -11,8 +11,8 @@
     <!-- A signature level permission granted only to the Firefox
          channels sharing an Android Account type. -->
     <permission
-        android:name="@MOZ_ANDROID_SHARED_FXACCOUNT_TYPE@.permission.PER_ACCOUNT_TYPE"
+        android:name="@ANDROID_PACKAGE_NAME@_fxaccount.permission.PER_ACCOUNT_TYPE"
         android:protectionLevel="signature">
     </permission>
 
-    <uses-permission android:name="@MOZ_ANDROID_SHARED_FXACCOUNT_TYPE@.permission.PER_ACCOUNT_TYPE" />
+    <uses-permission android:name="@ANDROID_PACKAGE_NAME@_fxaccount.permission.PER_ACCOUNT_TYPE" />
diff --git a/mobile/android/tests/background/junit3/Makefile.in b/mobile/android/tests/background/junit3/Makefile.in
index 7d35a01f6dc3..6cfd9d9176fe 100644
--- a/mobile/android/tests/background/junit3/Makefile.in
+++ b/mobile/android/tests/background/junit3/Makefile.in
@@ -13,7 +13,6 @@ manifest_FLAGS    += \
   -DANDROID_BACKGROUND_TARGET_PACKAGE_NAME='$(ANDROID_PACKAGE_NAME)' \
   -DANDROID_BACKGROUND_APP_DISPLAYNAME='$(MOZ_APP_DISPLAYNAME) Background Tests' \
   -DMOZ_ANDROID_SHARED_ID='$(ANDROID_PACKAGE_NAME).sharedID' \
-  -DMOZ_ANDROID_SHARED_ACCOUNT_TYPE='$(ANDROID_PACKAGE_NAME)_sync' \
   $(NULL)
 ANDROID_MANIFEST_FILE := $(CURDIR)/AndroidManifest.xml
 
diff --git a/mobile/android/tests/browser/robocop/Makefile.in b/mobile/android/tests/browser/robocop/Makefile.in
index 5f520768781b..17c5dae28f8e 100644
--- a/mobile/android/tests/browser/robocop/Makefile.in
+++ b/mobile/android/tests/browser/robocop/Makefile.in
@@ -39,7 +39,6 @@ manifest := $(srcdir)/AndroidManifest.xml.in
 manifest_TARGET := export
 manifest_FLAGS += \
   -DMOZ_ANDROID_SHARED_ID='$(ANDROID_PACKAGE_NAME).sharedID' \
-  -DMOZ_ANDROID_SHARED_ACCOUNT_TYPE='$(ANDROID_PACKAGE_NAME)_sync' \
   $(NULL)
 
 ANDROID_MANIFEST_FILE := $(CURDIR)/AndroidManifest.xml
diff --git a/services/sync/modules/util.js b/services/sync/modules/util.js
index 748e05196ec2..d36b6d25f390 100644
--- a/services/sync/modules/util.js
+++ b/services/sync/modules/util.js
@@ -614,30 +614,12 @@ this.Utils = {
    * Get the FxA identity hosts.
    */
   getSyncCredentialsHostsFxA: function() {
-    // This is somewhat expensive and the result static, so we cache the result.
-    if (this._syncCredentialsHostsFxA) {
-      return this._syncCredentialsHostsFxA;
-    }
     let result = new Set();
     // the FxA host
     result.add(FxAccountsCommon.FXA_PWDMGR_HOST);
-    //
-    // The FxA hosts - these almost certainly all have the same hostname, but
-    // better safe than sorry...
-    for (let prefName of ["identity.fxaccounts.remote.force_auth.uri",
-                          "identity.fxaccounts.remote.signup.uri",
-                          "identity.fxaccounts.remote.signin.uri",
-                          "identity.fxaccounts.settings.uri"]) {
-      let prefVal;
-      try {
-        prefVal = Services.prefs.getCharPref(prefName);
-      } catch (_) {
-        continue;
-      }
-      let uri = Services.io.newURI(prefVal, null, null);
-      result.add(uri.prePath);
-    }
-    return this._syncCredentialsHostsFxA = result;
+    // We used to include the FxA hosts (hence the Set() result) but we now
+    // don't give them special treatment (hence the Set() with exactly 1 item)
+    return result;
   },
 
   getDefaultDeviceName() {
diff --git a/toolkit/components/telemetry/Histograms.json b/toolkit/components/telemetry/Histograms.json
index 465aa1de8c59..fdeacf2ee51d 100644
--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -6800,371 +6800,476 @@
     "n_buckets": 1000,
     "description": "The time (in milliseconds) that it took an 'assign' request to go round trip."
   },
-  "DEVTOOLS_TOOLBOX_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's toolbox been opened?"
-  },
-  "DEVTOOLS_OPTIONS_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Options panel been opened?"
-  },
-  "DEVTOOLS_WEBCONSOLE_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Web Console been opened?"
-  },
-  "DEVTOOLS_BROWSERCONSOLE_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Browser Console been opened?"
-  },
-  "DEVTOOLS_INSPECTOR_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Inspector been opened?"
-  },
-  "DEVTOOLS_RULEVIEW_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Rule View been opened?"
-  },
-  "DEVTOOLS_COMPUTEDVIEW_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Computed View been opened?"
-  },
-  "DEVTOOLS_LAYOUTVIEW_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Layout View been opened?"
-  },
-  "DEVTOOLS_FONTINSPECTOR_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Font Inspector been opened?"
-  },
-  "DEVTOOLS_ANIMATIONINSPECTOR_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Animation Inspector been opened?"
-  },
-  "DEVTOOLS_JSDEBUGGER_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Debugger been opened?"
-  },
-  "DEVTOOLS_JSBROWSERDEBUGGER_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Browser Debugger been opened?"
-  },
-  "DEVTOOLS_STYLEEDITOR_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Style Editor been opened?"
-  },
-  "DEVTOOLS_SHADEREDITOR_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Shader Editor been opened?"
-  },
-  "DEVTOOLS_WEBAUDIOEDITOR_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Web Audio Editor been opened?"
-  },
-  "DEVTOOLS_CANVASDEBUGGER_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Canvas Debugger been opened?"
-  },
-  "DEVTOOLS_JSPROFILER_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's JS Profiler been opened?"
-  },
-  "DEVTOOLS_MEMORY_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Memory Tool been opened?"
-  },
-  "DEVTOOLS_NETMONITOR_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Network Monitor been opened?"
-  },
-  "DEVTOOLS_STORAGE_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the Storage Inspector been opened?"
-  },
-  "DEVTOOLS_PAINTFLASHING_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Paint Flashing been opened via the toolbox button?"
-  },
-  "DEVTOOLS_TILT_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Tilt been opened via the toolbox button?"
-  },
-  "DEVTOOLS_SCRATCHPAD_OPENED_BOOLEAN": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Scratchpad been opened via the toolbox button?"
-  },
-  "DEVTOOLS_SCRATCHPAD_WINDOW_OPENED_BOOLEAN": {
+  "DEVTOOLS_TOOLBOX_OPENED_COUNT": {
     "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
-    "expires_in_version": "50",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Scratchpad standalone window been opened?",
-    "bug_numbers": [1214352]
-  },
-  "DEVTOOLS_RESPONSIVE_OPENED_BOOLEAN": {
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Responsive View been opened via the toolbox button?"
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools toolbox has been opened.",
+    "releaseChannelCollection": "opt-out"
   },
-  "DEVTOOLS_EYEDROPPER_OPENED_BOOLEAN": {
+  "DEVTOOLS_OPTIONS_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Eyedropper tool been opened?"
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools options panel has been opened.",
+    "releaseChannelCollection": "opt-out"
   },
-  "DEVTOOLS_MENU_EYEDROPPER_OPENED_BOOLEAN": {
+  "DEVTOOLS_WEBCONSOLE_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's eyedropper been opened via the devtools menu?"
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Web Console has been opened.",
+    "releaseChannelCollection": "opt-out"
   },
-  "DEVTOOLS_PICKER_EYEDROPPER_OPENED_BOOLEAN": {
+  "DEVTOOLS_BROWSERCONSOLE_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's eyedropper been opened via the color picker?"
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Browser Console has been opened.",
+    "releaseChannelCollection": "opt-out"
   },
-  "DEVTOOLS_DEVELOPERTOOLBAR_OPENED_BOOLEAN": {
+  "DEVTOOLS_INSPECTOR_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the devtool's Developer Toolbar been opened via the toolbox button?"
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Inspector has been opened.",
+    "releaseChannelCollection": "opt-out"
   },
-  "DEVTOOLS_ABOUTDEBUGGING_OPENED_BOOLEAN": {
+  "DEVTOOLS_RULEVIEW_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Rule View has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_COMPUTEDVIEW_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Computed View has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_LAYOUTVIEW_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Layout View has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_FONTINSPECTOR_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Font Inspector has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_ANIMATIONINSPECTOR_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Animation Inspector has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_JSDEBUGGER_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Debugger has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_JSBROWSERDEBUGGER_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Browser Debugger has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_STYLEEDITOR_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Style Editor has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_SHADEREDITOR_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Shader Editor has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_WEBAUDIOEDITOR_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Web Audio Editor has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_CANVASDEBUGGER_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Canvas Debugger has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_JSPROFILER_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools JS Profiler has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_MEMORY_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Memory Tool has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_NETMONITOR_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Network Monitor has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_STORAGE_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Storage Inspector has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_PAINTFLASHING_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Paint Flashing has been opened via the toolbox button.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_TILT_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Tilt has been opened via the toolbox button.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_SCRATCHPAD_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Scratchpad has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_SCRATCHPAD_WINDOW_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1214352, 1247985],
+    "description": "Number of times the DevTools Scratchpad standalone window has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_RESPONSIVE_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Responsive Design Mode tool has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_EYEDROPPER_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Eyedropper tool has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_MENU_EYEDROPPER_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Eyedropper has been opened via the DevTools menu.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_PICKER_EYEDROPPER_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Eyedropper has been opened via the color picker.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_DEVELOPERTOOLBAR_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools Developer Toolbar / GCLI has been opened.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_ABOUTDEBUGGING_OPENED_COUNT": {
     "alert_emails": ["dev-developer-tools@lists.mozilla.org", "jan@mozilla.com"],
-    "expires_in_version": "55",
-    "kind": "boolean",
-    "description": "How many times has about:debugging been opened? (bug 1204601)"
-  },
-  "DEVTOOLS_WEBIDE_OPENED_BOOLEAN": {
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the DevTools WebIDE been opened?"
+    "kind": "count",
+    "bug_numbers": [1247985, 1204601],
+    "description": "Number of times about:debugging has been opened.",
+    "releaseChannelCollection": "opt-out"
   },
-  "DEVTOOLS_WEBIDE_PROJECT_EDITOR_OPENED_BOOLEAN": {
+  "DEVTOOLS_WEBIDE_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has the DevTools WebIDE project editor been opened?"
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools WebIDE has been opened.",
+    "releaseChannelCollection": "opt-out"
   },
-  "DEVTOOLS_WEBIDE_PROJECT_EDITOR_SAVE_BOOLEAN": {
+  "DEVTOOLS_WEBIDE_PROJECT_EDITOR_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has a file been saved in the DevTools WebIDE project editor?"
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times the DevTools WebIDE project editor has been opened.",
+    "releaseChannelCollection": "opt-out"
   },
-  "DEVTOOLS_WEBIDE_NEW_PROJECT_BOOLEAN": {
+  "DEVTOOLS_WEBIDE_PROJECT_EDITOR_SAVE_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has a new project been created in the DevTools WebIDE?"
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times a file has been saved in the DevTools WebIDE project editor.",
+    "releaseChannelCollection": "opt-out"
   },
-  "DEVTOOLS_WEBIDE_IMPORT_PROJECT_BOOLEAN": {
+  "DEVTOOLS_WEBIDE_NEW_PROJECT_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has a project been imported into the DevTools WebIDE?"
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times a new project has been created in the DevTools WebIDE.",
+    "releaseChannelCollection": "opt-out"
   },
-  "DEVTOOLS_CUSTOM_OPENED_BOOLEAN": {
+  "DEVTOOLS_WEBIDE_IMPORT_PROJECT_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
     "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "How many times has a custom developer tool been opened via the toolbox button?"
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times a project has been imported into the DevTools WebIDE.",
+    "releaseChannelCollection": "opt-out"
+  },
+  "DEVTOOLS_CUSTOM_OPENED_COUNT": {
+    "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
+    "expires_in_version": "never",
+    "kind": "count",
+    "bug_numbers": [1247985],
+    "description": "Number of times a custom developer tool has been opened.",
+    "releaseChannelCollection": "opt-out"
   },
   "DEVTOOLS_TOOLBOX_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many times has the devtool's toolbox been opened?"
+    "description": "Number of users that have opened the DevTools toolbox."
   },
   "DEVTOOLS_OPTIONS_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many times has the devtool's Options panel been opened?"
+    "description": "Number of users that have opened the DevTools Options panel."
   },
   "DEVTOOLS_WEBCONSOLE_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Web Console?"
+    "description": "Number of users that have opened the DevTools Web Console."
   },
   "DEVTOOLS_BROWSERCONSOLE_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Browser Console?"
+    "description": "Number of users that have opened the DevTools Browser Console."
   },
   "DEVTOOLS_INSPECTOR_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Inspector?"
+    "description": "Number of users that have opened the DevTools Inspector."
   },
   "DEVTOOLS_RULEVIEW_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Rule View?"
+    "description": "Number of users that have opened the DevTools Rule View."
   },
   "DEVTOOLS_COMPUTEDVIEW_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Computed View?"
+    "description": "Number of users that have opened the DevTools Computed View."
   },
   "DEVTOOLS_LAYOUTVIEW_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Layout View?"
+    "description": "Number of users that have opened the DevTools Layout View."
   },
   "DEVTOOLS_FONTINSPECTOR_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Font Inspector?"
+    "description": "Number of users that have opened the DevTools Font Inspector."
   },
   "DEVTOOLS_ANIMATIONINSPECTOR_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Animation Inspector?"
+    "description": "Number of users that have opened the DevTools Animation Inspector."
   },
   "DEVTOOLS_JSDEBUGGER_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Debugger?"
+    "description": "Number of users that have opened the DevTools Debugger."
   },
   "DEVTOOLS_JSBROWSERDEBUGGER_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Browser Debugger?"
+    "description": "Number of users that have opened the DevTools Browser Debugger."
   },
   "DEVTOOLS_STYLEEDITOR_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Style Editor?"
+    "description": "Number of users that have opened the DevTools Style Editor."
   },
   "DEVTOOLS_SHADEREDITOR_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Shader Editor?"
+    "description": "Number of users that have opened the DevTools Shader Editor."
   },
   "DEVTOOLS_WEBAUDIOEDITOR_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Web Audio Editor?"
+    "description": "Number of users that have opened the DevTools Web Audio Editor."
   },
   "DEVTOOLS_CANVASDEBUGGER_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Canvas Debugger?"
+    "description": "Number of users that have opened the DevTools Canvas Debugger."
   },
   "DEVTOOLS_JSPROFILER_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's JS Profiler?"
+    "description": "Number of users that have opened the DevTools JS Profiler."
   },
   "DEVTOOLS_MEMORY_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Memory Tool?"
+    "description": "Number of users that have opened the DevTools Memory Tool."
   },
   "DEVTOOLS_NETMONITOR_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Network Monitor?"
+    "description": "Number of users that have opened the DevTools Network Monitor."
   },
   "DEVTOOLS_STORAGE_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Storage Inspector?"
+    "description": "Number of users that have opened the DevTools Storage Inspector."
   },
   "DEVTOOLS_PAINTFLASHING_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Paint Flashing been opened via the toolbox button?"
+    "description": "Number of users that have opened the DevTools Paint Flashing via the toolbox button."
   },
   "DEVTOOLS_TILT_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Tilt been opened via the toolbox button?"
+    "description": "Number of users that have opened the DevTools Tilt via the toolbox button."
   },
   "DEVTOOLS_SCRATCHPAD_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Scratchpad been opened via the toolbox button?"
+    "description": "Number of users that have opened the DevTools Scratchpad."
   },
   "DEVTOOLS_SCRATCHPAD_WINDOW_OPENED_PER_USER_FLAG": {
     "alert_emails": ["dev-developer-tools@lists.mozilla.org"],
     "expires_in_version": "50",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Scratchpad standalone window been opened?",
+    "description": "Number of users that have opened the DevTools Scratchpad standalone window.",
     "bug_numbers": [1214352]
   },
   "DEVTOOLS_RESPONSIVE_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Responsive View been opened via the toolbox button?"
+    "description": "Number of users that have opened the DevTools Responsive Design Mode."
   },
   "DEVTOOLS_EYEDROPPER_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Eyedropper via the toolbox button?"
+    "description": "Number of users that have opened the DevTools Eyedropper via the toolbox button."
   },
   "DEVTOOLS_MENU_EYEDROPPER_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Eyedropper via the devtools menu?"
+    "description": "Number of users that have opened the DevTools Eyedropper via the devtools menu."
   },
   "DEVTOOLS_PICKER_EYEDROPPER_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Eyedropper via the color picker?"
+    "description": "Number of users that have opened the DevTools Eyedropper via the color picker."
   },
   "DEVTOOLS_DEVELOPERTOOLBAR_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the devtool's Developer Toolbar been opened via the toolbox button?"
+    "description": "Number of users that have opened the DevTools Developer Toolbar been opened via the toolbox button."
   },
   "DEVTOOLS_ABOUTDEBUGGING_OPENED_PER_USER_FLAG": {
     "alert_emails": ["dev-developer-tools@lists.mozilla.org", "jan@mozilla.com"],
     "expires_in_version": "55",
     "kind": "flag",
-    "description": "How many users have opened about:debugging? (bug 1204601)"
+    "description": "Number of users that have opened about:debugging. (bug 1204601)"
   },
   "DEVTOOLS_WEBIDE_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the DevTools WebIDE?"
+    "description": "Number of users that have opened the DevTools WebIDE."
   },
   "DEVTOOLS_WEBIDE_PROJECT_EDITOR_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened the DevTools WebIDE project editor?"
+    "description": "Number of users that have opened the DevTools WebIDE project editor."
   },
   "DEVTOOLS_WEBIDE_PROJECT_EDITOR_SAVE_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have saved a file in the DevTools WebIDE project editor?"
+    "description": "Number of users that have saved a file in the DevTools WebIDE project editor."
   },
   "DEVTOOLS_WEBIDE_NEW_PROJECT_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have created a new project in the DevTools WebIDE?"
+    "description": "Number of users that have created a new project in the DevTools WebIDE."
   },
   "DEVTOOLS_WEBIDE_IMPORT_PROJECT_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have imported a project into the DevTools WebIDE?"
+    "description": "Number of users that have imported a project into the DevTools WebIDE."
   },
   "DEVTOOLS_CUSTOM_OPENED_PER_USER_FLAG": {
     "expires_in_version": "never",
     "kind": "flag",
-    "description": "How many users have opened a custom developer tool via the toolbox button?"
+    "description": "Number of users that have opened a custom developer tool via the toolbox button."
   },
   "DEVTOOLS_TOOLBOX_TIME_ACTIVE_SECONDS": {
     "expires_in_version": "never",
diff --git a/toolkit/modules/WindowsRegistry.jsm b/toolkit/modules/WindowsRegistry.jsm
index 6bd0b9f7b91b..2e7a5ad39383 100644
--- a/toolkit/modules/WindowsRegistry.jsm
+++ b/toolkit/modules/WindowsRegistry.jsm
@@ -47,4 +47,30 @@ var WindowsRegistry = {
     }
     return undefined;
   },
+
+  /**
+   * Safely removes a key from the registry.
+   *
+   * @param aRoot
+   *        The root registry to use.
+   * @param aPath
+   *        The registry path to the key.
+   * @param aKey
+   *        The key name.
+   */
+  removeRegKey: function(aRoot, aPath, aKey) {
+    let registry = Cc["@mozilla.org/windows-registry-key;1"].
+                   createInstance(Ci.nsIWindowsRegKey);
+    try {
+      let mode = Ci.nsIWindowsRegKey.ACCESS_QUERY_VALUE |
+                 Ci.nsIWindowsRegKey.ACCESS_SET_VALUE;
+      registry.open(aRoot, aPath, mode);
+      if (registry.hasValue(aKey)) {
+        registry.removeValue(aKey);
+      }
+    } catch (ex) {
+    } finally {
+      registry.close();
+    }
+  }
 };
diff --git a/toolkit/themes/shared/in-content/common.inc.css b/toolkit/themes/shared/in-content/common.inc.css
index 95a37ca9722a..13803cf034d2 100644
--- a/toolkit/themes/shared/in-content/common.inc.css
+++ b/toolkit/themes/shared/in-content/common.inc.css
@@ -596,7 +596,8 @@ xul|*.radio-label-box {
   background-color: var(--in-content-category-background-hover);
 }
 
-*|*.category[selected] {
+*|*.category[selected],
+*|*.category.selected {
   background-color: var(--in-content-category-background-active);
   color: var(--in-content-category-text-selected);
   -moz-padding-start: 11px; /* compensate the 4px border */