The greatest user script engine on the Internet (a fork of Greasemonkey).
DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM can be navigated using a two-paned window displaying a variety of different views on the document and all nodes within.
Extension Auto-Installer is a helper for Firefox/SeaMonkey/Thunderbird extension developers: it allows automatically adding or updating browser extensions, e.g. via command line tools. This makes testing your changes easier.
Customizes the new tab page. Add more tiles. Add the launcher from Firefox start. Have a background image. Set new tile images and titles. See recently closed tabs. And more...
Cookie Monster provides proactive cookie management on a site or domain level basis, including 3rd party cookies. Via the status bar, it provides easy access to enhanced cookie functionality, while doing so in a non-intrusive manner.
Dead pages, broken links, the scourge of the internet. Powerhouse sites like Slashdot and Digg can bring a server to its knees. What do we do when a page is dead but we still want to see it? Call in the clerics, and perform a resurrection...
Expands the context menu's 'Search for' item into a list of installed search engines, allowing you to choose the engine you want to use for each search.
Bring back your personal and powerful Firefox Button!
Changes the Location Bar of Firefox into a Breadcrumb display with rich and interactive features.
Gives a possibility to create custom toolbarbuttons...
Install Browser Extensions straight from GitHub Repositories