Comment by mrweasel

While I'd agree, the issue with that solution is that validating against government issued identity solutions aren't always free. I don't know if this is the case with the UK digital ID, but the Danish version certainly isn't free to query. The Danish one has, to my knowledge, a solution that would allow you to do an age for a person, without getting any other information, so yes, the browser could do that, but there cryptographic bits ensure that now body messed with the header data is still missing. And again, who's suppose to pay for the API calls if the browser does it, Mozilla, Google, Microsoft... Ladybird?