The real ones is that Firefox Quantum is finally out for Android (Firefox for Android jumped from version 68.0 to 79.0), and this bought a completely new interface too.
Now, the new interface is very nice (bottom navigator bar FTW) and the browser is much faster, but it lost some features and there is a limited number of extensions available for now (Mozilla seems to be manually approving them).
So what happened? A small but vocal number of users complained and we get this news from The Register like this was the worse mistake ever. It is not.
Sure Mozilla could have managed this update better (losing settings seems pretty bad for example), but most users are probably pretty satisfied with the update. I couldn't use Firefox Android before (too slow compared to Chrome) and I was using Nightly (and afterwards Beta) just so I could get the performance improvements since the browser is so much faster. And also the new interface looks fantastic.