Tab groups were apparently a huge mess in the backend side of things, which is why they removed it. And Tree Tabs [1] seems to be doing something functional in

Tab groups were apparently a huge mess in the backend side of things, which is why they removed it. And Tree Tabs [1] seems to be doing something functional into the direction of tab groups. Maybe that works for you... [1]: https://addons.mozilla.org/en-US/firefox/addon/tree-tabs/ https://addons.mozilla.org/en-US/firefox/addon/tree-tabs/