Genuine question, does brave have ff's container extension? currently that's one of the thing that keeps holding me on ff. another big one is i test website on firefox so to not get carried away with features only available in chromium

Containers are experimental as of very recently. So they will soon, but expect it to be in development right now.

I also test on FF and I don't care much for chromium. I was just curious why the author chose to do this.