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
The browser would need to be allowed to parse it, as they're the ones displaying the content; it would imply, however, that adblockers and other extensions would no longer be allowed.