[aswan]

Is "I'm perfectly fine with a specific extension that does something against the AMO rules and want to install it" a thing that happens in practice? (this is an honest question, I haven't come across extensions that I was interested in but that have been explicitly banned)

My original comment was reacting to the description of signing as "nonsense" but there doesn't seem to be understanding of why it exists. In brief: Mozilla can (and does) block specific extensions when they are found to be doing something malicious. From what I have seen the bar for this is very high, this applies not just to extensions that do things like extract user data, but to those that do it in a deceptive way without disclosing to users what the extension does. Anyway, this blocking works based on a unique ID embedded in every extension. But if extensions were not signed, a bad extension could just claim to be "[e-mail]" or something, trivially evading blocking. Signing isn't about somebody passing judgement on individual extensions, it is about ensuring that addon IDs are unique and not spoofable. You might reasonably say that there should be a user option to disable the signing requirement, but how would this work exactly? You wouldn't want the user to have to affirm that they want this setting every time they start the browser, which means it has to be stored somewhere on disk with other user settings. But this is, again, trivially forgeable by any software that has write access to the part of the system where user preferences are stored. I don't believe that anybody at Mozilla wants to put arbitrary limits on how people can use Firefox, but they do have a strong interest in protecting users who don't have the technical savvy to evaluate the implementation of extensions they install (which I would hope anybody who is installing unsigned extensions does!) The system described above was built up (over the years!) in response to actual abuse of extensions by bad actors. The choice between having reasonable protections for the overwhelming majority of users versus offering flexibility in this case is a crummy one to have to make, but the compromise Mozilla settled on is allowing for unsigned extensions in developer edition, Nightly builds, or custom-made builds. You may personally prefer a different outcome for this decision but calling it "nonsense" or ascribing other motives to Mozilla sounds to me either uninformed or disingenuous (or maybe just unable to consider the reality of weighing the needs of different groups of users when making a decision like this).