Comment by fwn

On Firefox for Android all extensions must be present in the AMO store at the time of installation, no sideloading - even of signed addons.

Mozilla banned non-store extensions in their last Firefox for Android overhaul a few years ago and afaik does not plan to allow them again.

This is the reason why the anti-paywall extensions are all gone/DMCAed.

It's a massive power shift away from the user. No idea why Mozilla did that.