[Vinnl]

I think you're referring to Panorama View [1], introduced in Firefox 4 (2010). I think there are still extensions that replicate the experience [2].

There are many things different now that might make it work better this time. If not just that it's 14 years later, different UI, and the pattern being familiar from other browsers, might make a difference too. But no guarantees, of course.

(Note: I don't work on Tab Groups.)

[1] https://web.archive.org/web/20110613070035/http://www.azaras...

[2] https://addons.mozilla.org/firefox/addon/simple-tab-groups/ is widely used, but I'm not sure if it does the overview. Other extensions do.

[capitainenemo]

There's also https://bugzilla.mozilla.org/show_bug.cgi?id=1509350 filed in 2018 for restoring it, now duped against this official bug... https://bugzilla.mozilla.org/show_bug.cgi?id=1907090

[cxr]

Panorama from Firefox 4. Also called Tab Groups.