>>1731If you habitually have a billion tabs open (I'm ashamed but I'll be honest about it) then you can go into about:config and change browser.tabs.tabMinWidth to 0.
As long as you have a full screen width of tabs It'll get rid of everything except the first letter, which isn't exactly what you need but it's fairly close and a nice extremely lazy solution.
Too bad there's not a browser.tabs.tabMaxWidth value. You'd think there would be, but no.