With the version 130, Mozilla introduces a new navigation bar in Firefox for Android. If you don't like it, you can disable it in the "Secret Settings".
I was not a fan when it popped out on my screen. But, after sometime, it's pretty useful and saves a tap on the three dots button.
Makes a lot of sense to me that Mozilla Connect isn't the only input to the roadmap. Perhaps they did user testing and found that people were struggling to find the back button or use tabs, and they're testing if this makes some of those tasks easier.