My phone won't open xpi files and the only solutions I've been able to find is either create a html file in the same folder, which I don't know how to do on android, or download and install an extension which is ALSO only available as an xpi 🤦
Looks like it SHOULD work, but when I search for addons, I get quick (far too quick to select any of them m) flashes of gray rectangles where suggestions would normally be and no search results after I execute the search.
I'm beginning to suspect that the Firefox app is broken 😕
Well I use Fennec for Android from F-Droid, which has the option of using custom collections for addons.
I don't think it's possible yet on "normal" Firefox other than Nightly.