For those interested on the question of age verification and GNU/Linux: be aware that Systemd v261-rc1 was recently released. It now implements an optional birth date field in the JSON user database (see second item under “Other changes”).
The implementation of this field was prompted by age-verification or -attestation laws.
That’s fair. Authoritarianism across the board is inherently anti-free and will give rise to enshittified or unsecure software given enough time. We’re not only dealing with bigots that can’t stand living on the same planet as others they don’t understand, but also those that want strict authority and enforcement.