diff --git a/mail/base/content/extensionsOverlay.css b/mail/base/content/extensionsOverlay.css
deleted file mode 100644
index 9a2b0ce535..0000000000
--- a/mail/base/content/extensionsOverlay.css
+++ /dev/null
@@ -1,7 +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/. */
-
-.legacy-warning {
-  display: none;
-}
diff --git a/mail/base/content/mailCore.js b/mail/base/content/mailCore.js
index 6a043caf75..25ad3b8654 100644
--- a/mail/base/content/mailCore.js
+++ b/mail/base/content/mailCore.js
@@ -461,7 +461,7 @@ function openAddonsMgr(aView)
     }
   }
 
-  openContentTab("chrome://mozapps/content/extensions/extensions.xul", "tab", "addons.mozilla.org");
+  openContentTab("about:addons", "tab", "addons.mozilla.org");
 
 
   if (aView) {
diff --git a/mail/base/jar.mn b/mail/base/jar.mn
index 42f49ce6f9..63fe401a66 100644
--- a/mail/base/jar.mn
+++ b/mail/base/jar.mn
@@ -6,7 +6,6 @@ messenger.jar:
 % overlay chrome://global/content/viewSource.xul chrome://messenger/content/viewSourceOverlay.xul
 % overlay chrome://global/content/config.xul chrome://messenger/content/configEditorOverlay.xul
 % overlay chrome://editor/content/EdSpellCheck.xul chrome://messenger/content/EdSpellCheckOverlay.xul
-% style chrome://mozapps/content/extensions/extensions.xul chrome://messenger/content/extensionsOverlay.css
 % style chrome://global/content/customizeToolbar.xul chrome://messenger/content/messenger.css
 % style chrome://global/content/customizeToolbar.xul chrome://messenger/skin/
 % style chrome://global/content/customizeToolbar.xul chrome://messenger/skin/addressbook/addressbook.css
@@ -16,7 +15,6 @@ messenger.jar:
 % style chrome://global/content/customizeToolbar.xul chrome://messenger/skin/primaryToolbar.css
     content/messenger/mailWindow.js                 (content/mailWindow.js)
     content/messenger/messageDisplay.js             (content/messageDisplay.js)
-    content/messenger/extensionsOverlay.css         (content/extensionsOverlay.css)
     content/messenger/folderDisplay.js              (content/folderDisplay.js)
     content/messenger/mailWindowOverlay.js          (content/mailWindowOverlay.js)
 *   content/messenger/mailWindowOverlay.xul         (content/mailWindowOverlay.xul)