About:config
From MozillaZine Knowledge Base
about:config is a special location that lists all application preferences (read from "prefs.js" and "user.js"), many of which are not present in Options/Preferences dialog. Preferences can also be changed there.
Warning: Changing these values can, in rare circumstances, break Mozilla Suite, Firefox, or Thunderbird or cause strange behavior. Only edit these preferences if you know what you are doing.
Opening about:config
- In Firefox and Mozilla Suite, type "about:config" in the Location Bar and press Enter.
- In Thunderbird, use AboutConfig extension. (You will be able to access about:config from the menu in Thunderbird 1.5.)
- There's a version of AboutConfig extension compatible with Nvu here.
about:config entries
This article contains a list of valid about:config entries and their possible values. That article is a reference for what each preference does, it is not the place to edit your preferences.
References
- A brief guide to Mozilla preferences
- MozillaZine Tutorial for about:config — Step by step guide with screenshots.
- Preferential extension — An about:config-like extension that has some extra features (documentation for some of the preferences, for example).
- About protocol links — other about: pages.