I think the severity of this bug should be upped to at least "important".
The reasoning here is that any privacy-related add-on installed through Debian repositories is automatically (and silently) disabled on launch, leading to privacy leaks when opening a link in Firefox from another application (like a mail client or a chat application). So the issues related to this bug are not limited to quality of life, they can have a real impact on user privacy and could hurt the trust users have for the Debian-packaged versions of Firefox and WebExtensions.
