Reinstates the extensions.checkCompatibility preference without respect to the current application version.
Notifies you of sites affected by the Heartbleed vulnerability via an icon in the location bar using Mozilla's Heartbleed checker service.
Allows Personas to work in private browsing windows
Saves copies of already-installed add-ons.
Create and manage add-ons made from Greasemonkey and Scriptish user scripts
Fixes theming of about:home by Walnut and other such themes in Firefox 8+, where they were prevented from doing so.
Firefox for Vim and Links addicts.
A simple add-on for extension testers, especially AMO editors and developers who plan to submit their add-ons to AMO.
Theme testing helper
Change the URL opened for new, blank tabs.