As the link details, this is a project by Google to add a system not only to web clients, but also to web servers, that performs Device Attestation so that the website can control how, and if, a web browser or a machine in general can visit it.
As expected from Google, this is basically a combination of DRM and Anti-Adblock. They try to sell it as a way to """"only"""" perform nonidentifying checks, but in the same document in their section of open issues they leave to the air how to prevent their users (websites) from using it to discriminate web browsers that don't complain with certain criteria (such as "be Google Chrome").
There are various Issues opened already to let these people know the evil they are creating. One notable is here (28), and this social media thread follows the more general issue.
Getting real tired of even the tiny amount of openness and privacy we enjoy in computing being constantly under attack from every fucking angle. This will be another serious blow to general purpose computing if it happens. Fuck Google, fuck big tech, fuck the path we're headed down