Control what gets sent as the HTTP Referer on a per-site basis.
The greatest user script engine on the Internet (a fork of Greasemonkey).
Manage your installed personas (lightweight themes).
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.
Install Browser Extensions straight from GitHub Repositories
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.
Pretty-prints JSON content in the browser for easy, unobtrusive viewing.
Add more items to Add-ons Manager context menu.
Gives a possibility to create custom toolbarbuttons...
Offers the possibility to display documents in browser window.
Add "Go Parent Folder" menu to context menu in The Library list view and Search result in Bookmarks Sidebar.