In the language of Polandball comics, it means "give land/territory".
"Gib" is taken from the German imperative for "give!"
Best theory is that "clay" as "land" originates from a bad machine translation.
It seems somene created a Wiki that covers these terms: https://www.polandballwiki.com/wiki/Terminology#Clay
Well, it's about Peter Thiel, who also founded the Palantir surveillance technology company. As a source for his involvement with Brave, Wikipedia cites this TechCrunch article, which mentions funding from Thiel's "Founders Fund".
I'd rather criticize Brave for other reasons though, like being led by Brendan Eich or supporting crypto.