User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:71.0) Gecko/20100101 Firefox/71.0
Steps to reproduce:
I am a user of Bitwarden. Bitwarden is an open source password manager and a recommended extension (by Mozilla). It is also the second highest rated extension at addons.mozilla.org.
Bitwarden by default uses the shortcut Ctrl+Shift+L to fill username and password into login forms. As of recently, the same shortcut seems to be used for the Debugger (not yet on stable though). This leaves a conflict.
If you open the browser and use Bitwarden (= log in to Bitwarden) first, then the shortcut works as expected.
If you open the browser, use the shortcut before using Bitwarden (e.g. because you forgot to login to Bitwarden first) it opens the "Debugger" console. Even after you logged into Bitwarden, the shortcut now opens the Debugger. The only remedy is to restart Firefox. It is not transparent to the user why the shortcut behaves differently, especially if the user is not willing to test out when it misbehaves.
Users should expect a shortcut to always behave the same. Ctrl-Shift-L is a new shortcut for the Debugger that does not yet work in stable. Therefore I feel changes may be possible.
a) The Debugger shortcut could be placed on another key combination. As Bitwarden not only aligns with goals of privacy, security and free software but also is recommended by Mozilla itself this may warrant some kind of "special treatment" i.e. not breaking it's functionality for users.
b) It woud be possible to leave the Debugger on Ctrl-Shift-L but let the shortcut be superseded by any extension that also uses the shortcut. This would mean that as long as Bitwarden is installed, Ctrl-Shift-L would be reserved for the extension and not for the Debugger.
c) The worst outcome would be to leave it as is: The conflicting shortcuts would have to be resolved by the users and/or Bitwarden. While it is possible for an informed user to change extension shortcuts, this would break the users experience and need huge communication efforts.
d) In any case the resolution to the shortcut conflict (= both Debugger and Extension use the shortcut) is confusing at best. For the user it seems like a functionality randomly stops working. This argument is independent from Bitwarden. If appropriate I can open a new bug for this.