Originally from this post.
I wrote a Thunderbird extension (and my first one too!) that allows the display of all available about: windows in Thunderbird. Shredder Alpha 3 and above is required though. It is called ViewAbout and can be downloaded from Mozilla Add-ons. (Firefox 3.0.x and above are supported from version 1.2, other applications are continuously added and [hopefully] supported.)
about:, about:buildconfig, about:cache (and related), about:config, about:crashes, about:credits, about:license (generic Toolkit license), about:mozilla, about:neterror (seemingly useless), about:plugins, about:privatebrowsing, about:rights, about:robots, about:sessionrestore, about:weave.
These windows can be closed using Ctrl (or Cmd)-w. Note that some about: menu options may not show up in applications that do not support them.
Historical note: ViewAbout came about from a need to view about:crashes in Thunderbird, and it just expanded from there.
I have also made ViewAbout’s AMO Dashboard public, so everyone can see just how many users need about:crashes or about:config and the like.
Development of ViewAbout has now shifted to Google Code.
security validation. Re-enable about:neterror for those who love it for
complete-ness’ sake. Add support up to Firefox 3.7a1pre.
1.4.2: Fixed up nit in 1.4.1.
1.4.1: Now supports Instantbird 0.2 and up. Thanks Nils Maier! Tidied up contributors section.
1.4: Now supports Firefox 2.0.0.x. Auto-detection for available
about URLs in current application. Support for access keys in menu.
Some code re-factorizations to reduce redundant code. Huge thanks go
out to Dave Garrett for contributing this version.
1.2: Supports Firefox 3.0 and above. Supports Thunderbird 2.0 and above. (Note that some about: pages won’t show for Thunderbird 2.0.0.x because they’re based on an older Gecko 1.8.1.x branch)
1.1: Adds about:, about:cache, about:cache?device=disk, about:cache?device=memory and about:cache?device=offline. Removes Mac file metadata. Fixes error console error that pops up whenever an about: window is opened. Minor fixes.
1.0: Initial version.