Add-ons

User Agent Switcher by chrispederick

The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.

Session Manager by Michael Kraft

Session Manager saves and restores the state of all or some windows - either when you want it or automatically at startup and after crashes. It can also automatically save the state of open windows individually.

HttpFox by Martin Theimer

An HTTP analyzer addon for Firefox

AutoProxy by lovelywcm

Are you concerned about your privacy? Or, are you blocked from some websites by a firewall? And, are you arming yourself with a proxy? In that case, AutoProxy is designed for you! A tool to help you use your proxy automatically & efficiently.

Quick Locale Switcher by ppclick

Allows you to quickly switch to a different language (User Interface, Spell Checker Dictionary and Website content) in your Mozilla application.

Private Tab by Infocatcher

Adds private tabs.

Mycroft Project by Mycroft Project

The Mycroft Project is a collection of OpenSearch & Sherlock Search Engine Plugins for your internet browser.

about:addons-memory by Nils Maier

Adds an about:addons-memory page that details add-on memory usage

Extension Auto-Installer by Wladimir Palant

Important note: This extension will not work in Firefox 57 and above. Providing this functionality in Firefox is no longer possible, the extension is discontinued.

Developer Assistant by Ted Mielczarek, Gavin Sharp, others

A suite of tools for developers.

Restartless Restart by Erik Vold

This 15KB restartless add-on will add a "File" -> "Restart" menu item and a ctrl/cmd + alt + r hotkey to restart Firefox or Seamonkey.

XPCOMViewer by Ondřej Doněk

XPCOMViewer is tiny tool for exploring XPCOM components.

GitHub Extension Installer by Diego Casorran

Install Browser Extensions straight from GitHub Repositories

Moon In The Trees by Poppy

stonehenge - summer solstice - by snowdrop289