I used that on Opera way back in the day (before the Blink rewrite). Back then there weren't any Firefox extensions that I liked (either too complex or too 'jan

I used that on Opera way back in the day (before the Blink rewrite). Back then there weren't any Firefox extensions that I liked (either too complex or too 'janky', IIRC) so I just gave up on vertical tabs and grouping, but maybe I should look at it again as that was years ago. Thanks!