I'm agree with the community. Let's make out browser friendly. Vertical tabs it's very cool. You can try to make realization like in Vivaldi for example. Or you can implement TreeStyleTab addon. I believe that author will be happy to be a part of Moz...
I believe that vertical tabs it's important for the browser. Because realisation in Vivaldi for example are good. Or you can use tree style tab addon + function to hide horizontal ones. I believe that developer will be happy to be a part of Mozilla.
I'm agree 100%. Progressive apps very important. Fast, don't take a place on device and universal. Pls put it back, because we don't want to use another browsers.
