diff --git a/browser/components/extensions/moz.build b/browser/components/extensions/moz.build
index 0dfbc28ec7c9..62638aa3560f 100644
--- a/browser/components/extensions/moz.build
+++ b/browser/components/extensions/moz.build
@@ -27,12 +27,4 @@ BROWSER_CHROME_MANIFESTS += [
 ]
 
 MOCHITEST_MANIFESTS += ['test/mochitest/mochitest.ini']
-
-if CONFIG['OS_ARCH'] != 'Darwin':
-    XPCSHELL_TESTS_MANIFESTS += [
-        'test/xpcshell/xpcshell-remote.ini',
-    ]
-
-XPCSHELL_TESTS_MANIFESTS += [
-    'test/xpcshell/xpcshell.ini',
-]
+XPCSHELL_TESTS_MANIFESTS += ['test/xpcshell/xpcshell.ini']
diff --git a/browser/components/extensions/test/xpcshell/head.js b/browser/components/extensions/test/xpcshell/head.js
index 9d9a087b3e6c..6c4ce36871a6 100644
--- a/browser/components/extensions/test/xpcshell/head.js
+++ b/browser/components/extensions/test/xpcshell/head.js
@@ -4,7 +4,6 @@ const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 
 /* exported createHttpServer, promiseConsoleOutput  */
 
-Components.utils.import("resource://gre/modules/Services.jsm");
 Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "AppConstants",
@@ -25,11 +24,11 @@ XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
                                   "resource://gre/modules/NetUtil.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "Schemas",
                                   "resource://gre/modules/Schemas.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Services",
+                                  "resource://gre/modules/Services.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "TestUtils",
                                   "resource://testing-common/TestUtils.jsm");
 
-Services.prefs.setBoolPref("extensions.webextensions.remote", false);
-
 ExtensionTestUtils.init(this);
 
 
diff --git a/browser/components/extensions/test/xpcshell/head_remote.js b/browser/components/extensions/test/xpcshell/head_remote.js
deleted file mode 100644
index 35eb498f5083..000000000000
--- a/browser/components/extensions/test/xpcshell/head_remote.js
+++ /dev/null
@@ -1,4 +0,0 @@
-"use strict";
-
-Services.prefs.setBoolPref("extensions.webextensions.remote", true);
-Services.prefs.setIntPref("dom.ipc.keepProcessesAlive.extension", 1);
diff --git a/browser/components/extensions/test/xpcshell/xpcshell-common.ini b/browser/components/extensions/test/xpcshell/xpcshell-common.ini
deleted file mode 100644
index 0919d94fdf4c..000000000000
--- a/browser/components/extensions/test/xpcshell/xpcshell-common.ini
+++ /dev/null
@@ -1,8 +0,0 @@
-[test_ext_bookmarks.js]
-[test_ext_browsingData.js]
-[test_ext_browsingData_cookies_cache.js]
-[test_ext_browsingData_downloads.js]
-[test_ext_browsingData_passwords.js]
-[test_ext_browsingData_settings.js]
-[test_ext_history.js]
-[test_ext_geckoProfiler_control.js]
diff --git a/browser/components/extensions/test/xpcshell/xpcshell-remote.ini b/browser/components/extensions/test/xpcshell/xpcshell-remote.ini
deleted file mode 100644
index 3d6343394174..000000000000
--- a/browser/components/extensions/test/xpcshell/xpcshell-remote.ini
+++ /dev/null
@@ -1,7 +0,0 @@
-[DEFAULT]
-head = head.js head_remote.js
-firefox-appdir = browser
-tags = webextensions remote-webextensions
-dupe-manifest =
-
-[include:xpcshell-common.ini]
diff --git a/browser/components/extensions/test/xpcshell/xpcshell.ini b/browser/components/extensions/test/xpcshell/xpcshell.ini
index 107e45d92a75..770f7c2f323e 100644
--- a/browser/components/extensions/test/xpcshell/xpcshell.ini
+++ b/browser/components/extensions/test/xpcshell/xpcshell.ini
@@ -1,23 +1,16 @@
 [DEFAULT]
 head = head.js
 firefox-appdir = browser
-tags = webextensions in-process-webextensions
-dupe-manifest =
-
-# This file contains tests which are not affected by multi-process
-# configuration, or do not support out-of-process content or extensions
-# for one reason or another.
-#
-# Tests which are affected by remote content or remote extensions should
-# go in one of:
-#
-#  - xpcshell-common.ini
-#    For tests which should run in all configurations.
-#  - xpcshell-remote.ini
-#    For tests which should only run with both remote extensions and remote content.
+tags = webextensions
 
+[test_ext_bookmarks.js]
+[test_ext_browsingData.js]
+[test_ext_browsingData_cookies_cache.js]
+[test_ext_browsingData_downloads.js]
+[test_ext_browsingData_passwords.js]
+[test_ext_browsingData_settings.js]
+[test_ext_history.js]
 [test_ext_manifest_commands.js]
 [test_ext_manifest_omnibox.js]
 [test_ext_manifest_permissions.js]
-
-[include:xpcshell-common.ini]
+[test_ext_geckoProfiler_control.js]
diff --git a/toolkit/components/extensions/Extension.jsm b/toolkit/components/extensions/Extension.jsm
index ad3b3ea4ac99..d9484b9dbc6e 100644
--- a/toolkit/components/extensions/Extension.jsm
+++ b/toolkit/components/extensions/Extension.jsm
@@ -1100,11 +1100,6 @@ this.Extension = class extends ExtensionData {
 
     Services.ppmm.broadcastAsyncMessage("Extension:Shutdown", {id: this.id});
 
-    if (this.rootURI instanceof Ci.nsIJARURI) {
-      let file = this.rootURI.JARFile.QueryInterface(Ci.nsIFileURL).file;
-      Services.ppmm.broadcastAsyncMessage("Extension:FlushJarCache", {path: file.path});
-    }
-
     MessageChannel.abortResponses({extensionId: this.id});
 
     ExtensionManagement.shutdownExtension(this.uuid);
diff --git a/toolkit/components/extensions/moz.build b/toolkit/components/extensions/moz.build
index 1652b8f04bd6..9bb7f069b5d4 100644
--- a/toolkit/components/extensions/moz.build
+++ b/toolkit/components/extensions/moz.build
@@ -58,7 +58,6 @@ MOCHITEST_MANIFESTS += [
 MOCHITEST_CHROME_MANIFESTS += ['test/mochitest/chrome.ini']
 XPCSHELL_TESTS_MANIFESTS += [
     'test/xpcshell/native_messaging.ini',
-    'test/xpcshell/xpcshell-e10s.ini',
     'test/xpcshell/xpcshell-remote.ini',
     'test/xpcshell/xpcshell.ini',
 ]
diff --git a/toolkit/components/extensions/test/xpcshell/head.js b/toolkit/components/extensions/test/xpcshell/head.js
index 94945de910b5..a8f3458bb95f 100644
--- a/toolkit/components/extensions/test/xpcshell/head.js
+++ b/toolkit/components/extensions/test/xpcshell/head.js
@@ -5,7 +5,6 @@ const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 /* exported createHttpServer, promiseConsoleOutput, cleanupDir */
 
 Components.utils.import("resource://gre/modules/AppConstants.jsm");
-Components.utils.import("resource://gre/modules/Services.jsm");
 Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
 Components.utils.import("resource://gre/modules/Timer.jsm");
 Components.utils.import("resource://testing-common/AddonTestUtils.jsm");
@@ -28,8 +27,8 @@ XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
                                   "resource://gre/modules/NetUtil.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "Schemas",
                                   "resource://gre/modules/Schemas.jsm");
-
-Services.prefs.setBoolPref("extensions.webextensions.remote", false);
+XPCOMUtils.defineLazyModuleGetter(this, "Services",
+                                  "resource://gre/modules/Services.jsm");
 
 ExtensionTestUtils.init(this);
 
diff --git a/toolkit/components/extensions/test/xpcshell/head_e10s.js b/toolkit/components/extensions/test/xpcshell/head_e10s.js
deleted file mode 100644
index 55ff2164a10e..000000000000
--- a/toolkit/components/extensions/test/xpcshell/head_e10s.js
+++ /dev/null
@@ -1,5 +0,0 @@
-"use strict";
-
-/* globals ExtensionTestUtils */
-
-ExtensionTestUtils.remoteContentScripts = true;
diff --git a/toolkit/components/extensions/test/xpcshell/head_remote.js b/toolkit/components/extensions/test/xpcshell/head_remote.js
index 35eb498f5083..55ff2164a10e 100644
--- a/toolkit/components/extensions/test/xpcshell/head_remote.js
+++ b/toolkit/components/extensions/test/xpcshell/head_remote.js
@@ -1,4 +1,5 @@
 "use strict";
 
-Services.prefs.setBoolPref("extensions.webextensions.remote", true);
-Services.prefs.setIntPref("dom.ipc.keepProcessesAlive.extension", 1);
+/* globals ExtensionTestUtils */
+
+ExtensionTestUtils.remoteContentScripts = true;
diff --git a/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini b/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
index 32f73db633d8..f8833c227728 100644
--- a/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
+++ b/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
@@ -2,6 +2,7 @@
 [test_ext_alarms_does_not_fire.js]
 [test_ext_alarms_periodic.js]
 [test_ext_alarms_replaces.js]
+[test_ext_api_permissions.js]
 [test_ext_background_generated_load_events.js]
 [test_ext_background_generated_reload.js]
 [test_ext_background_global_history.js]
diff --git a/toolkit/components/extensions/test/xpcshell/xpcshell-e10s.ini b/toolkit/components/extensions/test/xpcshell/xpcshell-e10s.ini
deleted file mode 100644
index 4c4737bf4758..000000000000
--- a/toolkit/components/extensions/test/xpcshell/xpcshell-e10s.ini
+++ /dev/null
@@ -1,12 +0,0 @@
-[DEFAULT]
-head = head.js head_e10s.js
-tail =
-firefox-appdir = browser
-skip-if = appname == "thunderbird" || os == "android"
-dupe-manifest =
-support-files =
-  data/**
-  xpcshell-content.ini
-tags = webextensions webextensions-e10s
-
-[include:xpcshell-content.ini]
diff --git a/toolkit/components/extensions/test/xpcshell/xpcshell-remote.ini b/toolkit/components/extensions/test/xpcshell/xpcshell-remote.ini
index 8af28a476edc..7a0452810026 100644
--- a/toolkit/components/extensions/test/xpcshell/xpcshell-remote.ini
+++ b/toolkit/components/extensions/test/xpcshell/xpcshell-remote.ini
@@ -1,5 +1,5 @@
 [DEFAULT]
-head = head.js head_remote.js head_e10s.js
+head = head.js head_remote.js
 tail =
 firefox-appdir = browser
 skip-if = appname == "thunderbird" || os == "android"
@@ -7,7 +7,6 @@ dupe-manifest =
 support-files =
   data/**
   xpcshell-content.ini
-tags = webextensions remote-webextensions
+tags = webextensions webextensions-e10s
 
-[include:xpcshell-common.ini]
 [include:xpcshell-content.ini]
diff --git a/toolkit/components/extensions/test/xpcshell/xpcshell.ini b/toolkit/components/extensions/test/xpcshell/xpcshell.ini
index 7a0201784dd8..d23361aed852 100644
--- a/toolkit/components/extensions/test/xpcshell/xpcshell.ini
+++ b/toolkit/components/extensions/test/xpcshell/xpcshell.ini
@@ -7,48 +7,86 @@ support-files =
   data/**
   head_sync.js
   xpcshell-content.ini
-tags = webextensions in-process-webextensions
-
-# This file contains tests which are not affected by multi-process
-# configuration, or do not support out-of-process content or extensions
-# for one reason or another.
-#
-# Tests which are affected by remote content or remote extensions should
-# go in one of:
-#
-#  - xpcshell-common.ini
-#    For tests which should run in all configurations.
-#  - xpcshell-remote.ini
-#    For tests which should only run with both remote extensions and remote content.
-#  - xpcshell-content.ini
-#    For tests which rely on content pages, and should run in all configurations.
-#  - xpcshell-e10s.ini
-#    For tests which rely on conetn pages, and should only run with remote content
-#    but in-process extensions.
+tags = webextensions
 
 [test_csp_custom_policies.js]
 [test_csp_validator.js]
+[test_ext_alarms.js]
+[test_ext_alarms_does_not_fire.js]
+[test_ext_alarms_periodic.js]
+[test_ext_alarms_replaces.js]
+[test_ext_api_permissions.js]
+[test_ext_background_generated_load_events.js]
+[test_ext_background_generated_reload.js]
+[test_ext_background_global_history.js]
+skip-if = os == "android" # Android does not use Places for history.
+[test_ext_background_private_browsing.js]
+[test_ext_background_runtime_connect_params.js]
+[test_ext_background_sub_windows.js]
+[test_ext_background_window_properties.js]
+skip-if = os == "android"
 [test_ext_contexts.js]
+[test_ext_contextual_identities.js]
+skip-if = os == "android" # Containers are not exposed to android.
+[test_ext_debugging_utils.js]
+[test_ext_downloads.js]
+[test_ext_downloads_download.js]
+skip-if = os == "android"
+[test_ext_downloads_misc.js]
+skip-if = os == "android" || (os=='linux' && bits==32) # linux32: bug 1324870
+[test_ext_downloads_search.js]
+skip-if = os == "android"
+[test_ext_experiments.js]
+skip-if = release_or_beta
+[test_ext_extension.js]
+[test_ext_extensionPreferencesManager.js]
+[test_ext_extensionSettingsStore.js]
+[test_ext_idle.js]
 [test_ext_json_parser.js]
+[test_ext_localStorage.js]
+[test_ext_management.js]
+[test_ext_management_uninstall_self.js]
 [test_ext_manifest_content_security_policy.js]
 [test_ext_manifest_incognito.js]
 [test_ext_manifest_minimum_chrome_version.js]
 [test_ext_manifest_themes.js]
+[test_ext_onmessage_removelistener.js]
+skip-if = true # This test no longer tests what it is meant to test.
+[test_ext_permissions.js]
+skip-if = os == "android" # Bug 1350559
+[test_ext_privacy.js]
+[test_ext_privacy_disable.js]
+[test_ext_privacy_update.js]
+[test_ext_runtime_connect_no_receiver.js]
+[test_ext_runtime_getBrowserInfo.js]
+[test_ext_runtime_getPlatformInfo.js]
+[test_ext_runtime_onInstalled_and_onStartup.js]
+[test_ext_runtime_sendMessage.js]
+[test_ext_runtime_sendMessage_args.js]
+[test_ext_runtime_sendMessage_errors.js]
+[test_ext_runtime_sendMessage_no_receiver.js]
+[test_ext_runtime_sendMessage_self.js]
 [test_ext_schemas.js]
 [test_ext_schemas_async.js]
 [test_ext_schemas_allowed_contexts.js]
 [test_ext_schemas_revoke.js]
+[test_ext_shutdown_cleanup.js]
+[test_ext_simple.js]
+[test_ext_startup_cache.js]
+[test_ext_storage.js]
+[test_ext_storage_sync.js]
+head = head.js head_sync.js
+skip-if = os == "android"
+[test_ext_storage_sync_crypto.js]
+skip-if = os == "android"
 [test_ext_themes_supported_properties.js]
-[test_locale_converter.js]
-[test_locale_data.js]
-
-[test_ext_permissions.js]
-skip-if = os == "android" # Bug 1350559
-[test_ext_api_permissions.js]
-
+[test_ext_topSites.js]
+skip-if = os == "android"
 [test_ext_legacy_extension_context.js]
 [test_ext_legacy_extension_embedding.js]
+[test_locale_converter.js]
+[test_locale_data.js]
+[test_native_messaging.js]
+skip-if = os == "android"
 [test_proxy_scripts.js]
-
-[include:xpcshell-common.ini]
 [include:xpcshell-content.ini]