I use Tree Style Tab in the most recent firefox with a couple of style customizations: https://github.com/cweagans/dotfiles/blob/master/.mozilla/firefox/Profile

I use Tree Style Tab in the most recent firefox with a couple of style customizations: https://github.com/cweagans/dotfiles/blob/master/.mozilla/firefox/Profiles/default/chrome/userChrome.css#L41-L48 https://github.com/cweagans/dotfiles/blob/master/.mozilla/fi... Works great.