Отлично работает.

i installed it and my 99 million tabs that were opened went dark instantly, thank you letting my melting eye balls rest.

New: BEST addon until W3C FINALLY adopts my draft at github... (github.com/WICG/proposals/issues/125)
Old: Addon setting "browserdesign" should be set to "default" by default, not "customized", because on customized it destroys all webExtension themes......

This extensions helped me a lot. I am very happy for finally getting this add-on, I had been finding this for a long time. Thanks! Alexander Shutau for this !