Firefox 89 released with new UI

Say hello to a fresh new Firefox, designed to get you where you want to go even faster. We've redesigned and modernized the core experience to be cleaner, more inviting, and easier to use.

I was all set to dislike the new design, but honestly, on Linux - both on Gtk+ and KDE desktops, it looks and feels... Nice? I got used to it in an instant, and everything definitely looks cleaner, tighter, and fresher, without really making any massive changes or doing any truly drastic user interface overhauls.