By default now Firefox for Android shares an extra link with TRACKING for advertising itself. This is the features that everyone loves.
Ok, buried in the menu there's an option to disable this shit. But it's infuriating that a "please spam my friends and track the opening rate of my links" option is enabled by default
It's not as hardened (which can be a good or bad thing if your priorities are ease of use vs. privacy), but it's a debloated fork of Firefox, so it should be fine.