This morning I was distressed to find my version of Firefox had automatically updated and my tab groups were gone. Noooo! However, I'm pleased to have found this new replacement. I've been using it about 10 minutes so far ;-) My only suggestions at this point would be the option to name the groups, and to be able to drag and drop between groups. Other than that, THANK YOU for creating this. I don't want to go back to the stone ages with all my tabs open at the top.
Have a great day! :)