@JdeBP Okay, I’ve finally read this and… I don’t actually hate it. If I understand correctly, I believe any *nix system can comply with this by:

• Creating four groups, one for each age group specified in the law.
• Creating a database to hold the dates of birth of all accounts that correspond to a human (probably a flat file, given that it’s key-value pairs of date and uid).
• Creating a cron job that runs daily, checks each user against the database and, if it’s their birthday, checks whether their group membership needs updating.
• Updating user-add scripts and GUIs to ask for the date of birth if creating an account for a human.

Any application can then query which age group a person is in by querying group membership and web browsers can expose this.

A child with root can bypass the mechanism, but it gives a tool for parents to set age restrictions if they wish and to allow supervised privileged access. It does not require any verification of the age.

It looks a lot more sensible than the UK’s Online Safety Act, which ends up requiring a load of privacy-invasive things.