Correct me if I'm wrong, but wasn't v57, the Quantum update, the one that broke legacy Firefox extensions? There's nothing in Firefox 79's changelog that indicates they broke the newer kind of extensions (WebExtensions). Even BPIP addon history on Mozilla's site shows it only installs on v57 or above.
And by the way, Tor Browser is always based on an Firefox ESR version, eventually they are going to rebase from 68 ESR to 78 ESR so even if 79 has breaking changes I'm not aware of, Tor Browser should still be fine.
TBH I'm not entirely certain if 78 or 79 breaks it, or if it's even in the Firefox "core" code or just some stupid feature specific to the mobile version. But it's not an API issue (I could deal with that), it's the fact that the browser allows only (a subset of?) "recommended" extensions to be installed:
https://support.mozilla.org/en-US/kb/find-and-install-add-ons-firefox-androidYou can install a limited number of extensions from the Recommended Extensions program to add features to Firefox for Android. This article explains how to find, install and manage these extensions.
It's basically a "walled garden" type of setup and a niche extension like BPIP has no chance of getting in there.
I believe it's only in Firefox for Android codename Fenix. I found an article, that's not from Mozilla as they're weirdly secretive about the details, about it:
https://www.ctrl.blog/entry/review-firefox-fenix-android.htmlIn iOS Firefox must use Webkit engine so it's not affected by this. Desktop uses Gecko engine and not the Geckoview engine they recently created for android that locks to recommended extensions. So this seems to be an Android-specific feature.
The list of supported extensions has been dramatically cut from 8300 to 9. All extensions, other than the nine supported ones, are disabled when you upgrade to Fenix.
...
Mozilla has prepared no documentation, and there is no process that extension developers can follow to make their extensions available to Fenix users.
It's a shitty situation overall, but at least Nightly's getting a switch to load any arbitrary addon.
Can I run an arbitrary extension on a pre-release build of Firefox for Android?
We’re working on building a
pref for Nightly to allow persistent loading of an arbitrary extension. Once we have more details, we’ll post updates to the Add-ons Blog.