Haha, that is being added by Brave (browser). One of its features is intended to allow content creators to divest from advertising by accepting automatically apportioned donations of a cryptocurrency called Basic Attention Token, which users are supposed to be able to accrue by allowing vetted ads to be displayed. I don't bother with it, personally. It sounds like a pretty neat idea, but I think it would require widespread adoption, and most people don't even trust or bother with the largest cryptocurrency. Also, crypto as it is currently envisioned is a pitfall for people who cannot imagine simply improving society to the point where you do not need a super secret money to sidestep your own government.