You also have a list of all open tabs available from the dropdown arrow at the far right, but the tab width can be changed in about:config with browser.tabs.tabMinWidth.
If you're looking for information on this preference, it went away between FF4 and FF57(?) but should be back and working now so you'll see a lot of old information about it being removed.
If you're looking for information on this preference, it went away between FF4 and FF57(?) but should be back and working now so you'll see a lot of old information about it being removed.
Edit: FF58, https://bugzilla.mozilla.org/show_bug.cgi?id=1404465