about about

about URI scheme From Wikipedia, the free encyclopedia


This is a list of “about” pages for your convenience.
Some of them might be confusing. Some are for diagnostic purposes only.
And some are omitted because they require query strings.

Mozilla-specific about: URIs

Many of these can also be used in Thunderbird, by setting them as the "Mail Start Page". Also, some extensions define additional about: URIs not listed here.[9]

Mozilla-specific about: URIs
URIsMozilla Application Suite / SeaMonkeyMozilla Firefox
about:addons Shows installed addons, plugins, themes, and provides an interface for installing new addons. Firefox 4+, SeaMonkey 2.1+
about:app-manager   Shows the Firefox OS Simulator.
about:bloat   Displays BloatView output (disabled in release builds). Superseded by about:memory on Gecko 1.9.2.[10]
about:bloat?new   TBA
about:bloat?clear   TBA
about:blocked   Shows the malware protection page used when the browser identifies a page as not safe for viewing. Firefox 3+
about:buildconfig Shows the arguments and options used to compile the build in use.
about:cache Shows information about the Cache Service. Number of entries, location of cache, size of cache, etc. for both memory and disk cache.
about:cache?device=memory Shows individual entries in memory.
about:cache?device=disk Shows individual entries on disk.
about:cache?device=offline Shows individual entries for offline viewing. Gecko 1.9+
about:cache-entry Shows information about a cache entry. Used in about:cache links. Requires parameters.
about:certerror Shows the error page used when an SSL/TLS certificate is untrusted or otherwise invalid.
about:config Shows an interface for viewing and setting a wide variety of configuration variables, many of which are not otherwise accessible through the GUI (options panels). It displays a message which tells the user that the settings might void the warranty and they can be "Harmful to the stability, security, and performance of this application." The message about voiding one's warranty is a joke, as Mozilla Firefox ships without a warranty of any kind.[11]
about:crashes Shows details of crashes submitted by Mozilla's crash reporter. Firefox 3+, SeaMonkey 2.0+
about:credits Shows a list of all those who contributed to Mozilla.
about:downloads Shows a list of downloaded files.
about:feeds Shows the page used when clicking the rss feed icon in the address bar.
about:healthreport Shows the Firefox Health Report.
about:home   Shows the Firefox 4 default home page.
about:jetpack   Shows an interface for viewing and setting the JetPack extension.
about:kitchensink Was never included in Mozilla for the reasons listed in bug 122411 ("Mozilla does not have a kitchen sink"). A Firefox extension that adds it can be installed. (In SeaMonkey, the above-mentioned XML page would need to be bookmarked, copied, or SeaMonkey added to the extension's install.rdf. In SeaMonkey or Thunderbird, the Mail Start Page can be changed.)
about:licence In the British English localised version, shows the content of about:license but with all occurrences of license used as a noun replaced with licence (see American and British English spelling differences). Not available in Firefox 4
about:license Shows the Mozilla Public License (and the Netscape Public License) for the piece of software. Gecko 1.8+
about:logo Shows the logo used on the about: screen.
about:memory Shows memory usage. Firefox 3.6+
about:mozilla Easter egg, shows a verse from The Book of Mozilla.
about:neterror Shows the error page used when the browser could not access the requested path.
about:newaddon   This dialog is shown when one or more add-ons have been added without using the normal Add-on Manager procedures, by dropping it in one of the "special" add-on directories. It asks which ones to keep enabled.

Typing about:newaddon in the URL bar won't display anything. (It may briefly flash an empty error dialog, then the empty about:blank page is displayed.)

about:newtab Shows a grid of favourite and most-visited websites, Firefox 13+.
about:permissions   Shows permissions for all sites on Firefox 6.0a1.
about:plugins Shows installed, currently enabled plug-ins.
about:preferences Shows the new preferences page.
about:privatebrowsing   Can be used to switch to private browsing mode. It shows a message indicating that Firefox will not remember any history for the current session. Note: It does not show URI on the address bar.
about:rights Shows licensing information.
about:robots   Easter egg, beginning with March 8, 2008 trunk builds. The title of a window contains a citation from The Day the Earth Stood Still.[12]
about:searchreset   TBA
about:sessionrestore Shows an interface for viewing about last session.
about:socialerror   TBA
about:startpage In Ubuntu, shows the Ubuntu start page with the current search engine (if the addon Ubuntu Firefox Modifications – ubufox is installed).
about:support Shows troubleshooting information. Firefox 3.6+, SeaMonkey 2.1+
about:sync-tabs Shows list of tabs from other computers. Requires enabled synchronization.
about:tabcrashed   TBA. Firefox 25+
about:webrtc Shows an interface for WebRTC internals.