“whether … Brave or … Chromium is a separate matter”
Best UA for tor anonymity is the matter at hand. One can’t throw a UA string out sans metrics. That’s waving hands. I hope we’re on the same page in one regard? Brave should transmit different UAs in tor tabs than regular. Maybe you were thinking of a global UA string across all tabs; I’m not.
A tor dev said, “The Tor Browser has a unique fingerprint, this is unavoidable as long as other browsers don’t care about privacy issues. But ideally it should be the very same on every different computers it is used so that we all belong in one anonymity set.”
Underscore: ONE ANONYMITY SET.
“None of this has to do with anonymity among Brave users.”
That’s ANOTHER SET. It’s erroneous to conflate the two.
“My only point is … you are going to stand out among Brave users and thus it generally hurts your anonymity.”
No. The point of tor is to POOL TOR USERS. Making Brave users indistinguishable among themselves does not help them on tor. They need to pool with tor users, not Brave users.
By your claims we could just as well use a ‘Brave Anonynet’ apart from tor. Why? The Brave subset on tor is easy to nail.
Think numbers. Tor slows browsing. Only those keen will use it, not the whole Brave user base. So if (say) only 30 Braves use tor at once, among (say) 10000 generic tor users, the Brave folk stand out like neon signs. Just by UA string, no other reason.
Quibbling behavior argues naught against a minimal defense UA, trivial to implement. Full UA customization is debatable, not a choice based on pooling stats. Deeper fingerprinting just means Brave has more work to support tor. Don’t make the perfect the enemy of the best. Ask tor project advice.