Does seem broken for me.

Their piefed is up: https://piefed.blahaj.zone/

Its never just “A little extra code”. Each browser will have to implement it themselves (although possibly it could be done in chrome and everyone else inherits it by default), each browser will run the features through the standard debates around support, necessity, correctness, side channel security issues, etc. Firefox might drag their feet, chrome might implement it differently, edge might strip it out because it hurts their scraper. 5 years later it might get useful.

Keep in mind that any browser side extension runs the risk of breaking access for smaller browsers, so it can’t be used until there is near 100% market saturation, which could take years.

And you have to be very careful not to break accessibility for blind/etc users, who may have a non standard browser to begin with.

It would be nice if the AI robots.txt thing could be legally enforced.