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
I am very pessimistic but even I dont think mozzilla will abandon gecko. For one it works, also it is all they have.