I don't get this. Many years ago there was "Do not track", a header that was sent based on browser configuration. As a data subject, I loved it. As an engineer I also loved it - it was easy. If the header was present don't render any tracking code. If all services acted in good faith, it could have been epic. But there was pushback, and it went away. Sadface.

For what it's worth I think the browser is the right place for tools like this. If the same thing could have been applied to cookies, we'd not be experience cookie-preference-popupageddon.

The article suggests browser vendors are somehow on the hook for implementing "do not sell". Is the idea the same as do not track?