[cassianoleal]

> - some browsers do tabs below the address bar

Not Chrome though, so I don't see the relevance. I also don't like it. The address is relevant to that tab only, so it should be hierarchically inside it.

> - Firefox has tab scrolling, minimum tab widths, and the tab itself is a floating box, not a part of the page visually.

So, visual tweaks? Fine, but I don't see how that would improve UX massively.

> - Firefox's address bar is also different, to me it seems potentially also should be A/B tested with directly copying Chrome

Perhaps. Or maybe there's a lot of people who prefer Firefox's. In any case, again - visual tweaks?

I really don't see how any of those would bring great improvements to the Firefox experience.