In Firefox for Android Nightly, you can (since recently) sideload extensions via the hidden debug menu (tap the Firefox logo in the About section a dozen times). This will add an "Install extension from file" option to the main settings menu.

I don't know whether this also works in the standard version of Firefox for Android.

It is good they reenabled this feature. Since it is/was very short-sighted of Mozilla to make their centralized addon store the single gatekeeper for extension access on user devices. As if they never thought about power dynamics in software.

Pretty sure that's the version that kept calling Google Analytics, and why we got a clean fork "Bypass Paywalls Clean".

EDIT: Actually, never mind, this isn't even that, this is a fake according to the reviews.

Oh yes the one I mean is Bypass Paywalls Clean (D). But this also seems to have been kicked out of the Mozilla store. It was just a resubmit by someone else after the original got kicked out when a French newspaper complained.

We really need sideloading capability in mobile firefox :(

You can sideload in Firefox Android beta branch.

Settings> about Firefox> tap on the fox logo a few times> debug menu enabled> now you see "install ad on from file" under advanced in the settings menu.

Wow they finally added this?? Wow. I will try that thanks!