No details of course, so also see the 38C3 talk on EU digital identity wallets[1] which came up in the EU age verification app thread[2]:

– Authenticate RPs: no over-asking

– Unobservability: keys on user devices

– Selective disclosure: minimal attributes

– Unlinkability: ZKP-based anonymous credentials

– Deniability: designated-verifier ZKPs

[1] https://media.ccc.de/v/38c3-eu-s-digital-identity-systems-re...

[2] https://news.ycombinator.com/item?id=45359074