The next major version of Firefox will have a new add-ons manager.
The future Firefox continues to unfold gradually. A nightly of Firefox 3.7 that is sometimes called Firefox.next and who should ultimately be called Firefox 4.0, left shows a New Add-ons Manager. Mozilla is a project that has long lead.
Currently, the add-ons manager is relatively unobtrusive. It is to get the Tools menu to open a new window with the user can manage extensions, themes and plugins. The new manager will open it directly on a Firefox tab and add a string to his bow with the management Search Engines. Presumably, this manager will manage all the supplements to Firefox.