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
remember those website that say “oh you are using an ad blocker so disable it to access our site”
I can easily imagine this not being a necessary, anymore. Just let the website using this WEI API automatically disable all browser extensions on a WEI-enabled site. Why not, after all? Why should you dictate the traffic you receive on your computer? Why should you own anything?