Comment by Bender

That would be also nice, but given we can't make everyone to do the most basic interoperability I don't see it working…

Many moons ago there were a couple browsers that looked for the ICRA PICS label but the adoption was low due to complexity of the header creation and a lack of laws requiring it. I expect it would take an intern an afternoon to create the code to look for the RTA header and probably a couple weeks to get through the QA/staging process. It only needs to initially get into Chrome, Safari, Edge and Firefox to protect small children on a tablet with kids using a normie account and parents retaining the super-user account. Should a law pass that has a timeline for the check to be mandatory I expect a majority of web agents to recognize and act on the RTA header long before the deadline.

It would be 100% more than what we have today is nothing in the browser and privacy invading third parties that would not be involved in kids going to sites that do not force people into said third party sites which is most of them. To be a fly on the wall when someone tries to force the third party ID checks on 4chan...