looks like rendering adblockers extensions obsolete with manifest-v3 was not enough so now they try to implement DRM into the browser giving the ability to any website to refuse traffic to you if you don't run a complaint browser ( cough...firefox )
here is an article in hacker news since i'm sure they can explain this to you better than i.
and also some github docs
No for-profit is nice, but they are the lesser shit of the two choices we have. Remember that the Mozilla Corporation is a for-profit, the Mozilla Organization is a non-profit. There is a clear conflict of interest between those two entities.
I do and will continue to use their browser because it's the only choice I have if I want to stand by my principle of supporting a free and open web.