Version 15.2 is incredible! Rated 5 out of 5 stars
15.1 of this theme was the first to work for me (as long as I had Custom Tab Width installed, so it worked with many tabs).
Yet ... version 15.2 works very well with many tabs, the Add-ons panel looks good for the very first time (Mozilla, consider this for the default theme on Windows/Linux!).
Oh, and Firefox now looks like a GNOME window when deactivated.
Full marks. Thank you.