User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:56.0) Gecko/20100101 Firefox/56.0 Build ID: 20171027085204 Steps to reproduce: Allow extensions to open `about:addons` from the tabs API (and/or elsewhere). We don't need to send anchor or query strings. This bug is a requested leaf of 1269456. In that bug Boris said "Right. I strongly suspect allowing that particular string is not a problem." https://bugzilla.mozilla.org/show_bug.cgi?id=1269456#c40

Use case is addons that replace the Firefox UI want to be able to send users to the pages they ask for. (e.g. user types "open about:addons" in my commandline, I want to be able to send them to that URL). Add-ons affected: Tridactyl, Vimium, Vim-vixen, etc.

Also affected: gesture add-ons, etc.

Note that the command to open the Add-ons Manager has some logic to focus the window and tab where it is already open if it's possible; it would be good that the API manages it too, instead of leaving it to be replicated manually by all add-on. (In reply to Colin Caine from comment #0) > We don't need to send anchor or query strings. Besides offering the action to open about:addons as a generic command, I want to see possible letting to open a specific pane of the Add-ons Manager too: theming-related webextensions could then offer an additional command "manage your themes" for the stuff that these add-ons can't manipulate directly; an add-on to help you to install language packs from archive.mozilla.org in pre-release builds would have a "Manage your language packs" command (my legacy Simple Locale Switcher add-on has it). The same for Dictionaries/Available Updates/Recent Updates.

There's foundational work that needs to happen first. See https://bugzilla.mozilla.org/show_bug.cgi?id=1269456#c54