Where can I find a complete list (reference) of all Firefox about:config preference settings?

Note that a complete list of all preferences doesn't exist and would be very hard to maintain as a lot of prefs only last for a short time and are used in some Firefox versions and update channel. The list posted in the link posted above seems to be for a rather old Mozilla version since it includes mail prefs and other prefs not used in a regular Firefox build. If you want to know what is pref is about then search the Firefox source code. *https://searchfox.org/mozilla-release You can also look at the comments in files like these: *https://searchfox.org/mozilla-release/source/modules/libpref/init/StaticPrefList.yaml *https://searchfox.org/mozilla-release/source/browser/app/profile/firefox.js *https://searchfox.org/mozilla-release/source/modules/libpref/init/all.js