about:* firefox

list

     about: — The same page as "Help -> About" (except that, on some applications, Help → About is a much smaller popup).
    about:about — Lists all these about: URLs (Mozilla Suite/SeaMonkey or Firefox 4 and newer only).
    about:accounts — Firefox Sync account. New on Firefox 29. [1][2]
    about:addons — The "new" addons manager, in trunk builds dated 2010-05-11 or later.
    about:app-manager — new on Firefox 26. App Manager, a tool to help users build and install web apps on compatible devices (i.e. Firefox OS).
    about:buildconfig — Reveals details about your Mozilla build options.
    about:cache — Displays cache statistics and disk cache directory location.
        about:cache?device=memory — Lists memory cache entries.
        about:cache?device=disk — Lists disk cache entries. 
    about:cache-entry — Shows information about a cache entry. Used in about:cache links. Requires parameters.
    about:compartments shows a list of live JavaScript compartments [3]. Implemented starting with Firefox 13 (bug 702300)
    about:config — GUI for modifying user preferences. (Also accessible in Thunderbird by means of the "Config Editor" button in the "Advanced" Preferences).
    about:crashes — List of Breakpad crash reports, with links and datestamps. Only in products based on Gecko 1.9 or later (Firefox 3, Thunderbird 3, SeaMonkey 2).
    about:customizing — Only available on Australis.
    about:credits — The list of contributors to the Mozilla projects.
    about:data — opens the Data Manager which shows per-site data and permissions. This is part of SeaMonkey 2.x and available as a Firefox extension.
    about:downloads — new on Firefox 20. (Also in recent versions of SeaMonkey. Jökulsárlón Download Manager may be required.)
    about:home — Firefox Start Page
    about:healthreport — new on Firefox 21 (bug 718066, bug 719484). Also accessible via "Help -> Firefox Health Report".
    about:licence and about:license — both show the Mozilla Public License and the Netscape Public License for the piece of software. ( Only in products based on Gecko 1.8 or later)
    about:logo — Displays the application logo (Mozilla Suite, SeaMonkey, and Firefox 3).
    about:memory shows the memory usage of Firefox starting in Firefox 3.6 (Windows) and Firefox 4 (Linux). Implemented in bug 515354
    about:mozilla — The famous Book of Mozilla
    about:networking — new on Firefox 26.
    about:newtab — the default new tab page since Firefox 13.
    about:permissions shows and manages website permissions as also shown in Tools → Page Info → Permissions. Implemented starting in Firefox 6 (bug 573176). Note: about:permissions has been removed, starting in Firefox 45 (bug 933917).
    about:plugins — Lists all your plugins as well as other useful information.
    about:preferences — Firefox only. Open preferences.
    about:privatebrowsing
    about:rights
    about:robots — Easter egg, see bug 417302. Beginning with March 8th, 2008 trunk builds, it's now available on Firefox 3.0b5.
    about:sessionrestore
    about:support — Starting in Firefox 3.6 (bug 367596) and SeaMonkey 2.1a trunk builds based on Gecko 1.9.3a (bug 518607). Displays information such as Application Basics (version, link to open the profile folder, link to about:plugins and about:buildconfig), Extensions, Modified Preferences and, starting in Firefox 4, Graphics information (bug 587102). Also accessible via "Help -> Troubleshooting information".
    about:sync-log
    about:sync-progress
    about:sync-tab
    about:telemetry — new on Firefox/Thunderbird 19 and SeaMonkey 2.16 (bug 661881)
    about:webrtc — TBA
    about:welcomeback — new on Firefox 25. 

source

http://kb.mozillazine.org/About_protocol_links