Systemd isn’t implementing age verification. They added the ability to store the data because the xdg-desktop-portal team added the ability to set an age and that requires a place to store the data. No component ‘verifies’ the age, it’s a data field that you can enter whatever you’d like into. From github.com/systemd/systemd/pull/40954 : Stores the user’s birth date for age verification, as required by recent laws in California (AB-1043), Colorado (SB26-051), Brazil (Lei 15.211/2025), etc. The xdg-desktop-portal project is adding an age verification portal (flatpak/xdg-desktop-portal#1922) that needs a data source for the user’s age. userdb already stores personal metadata (emailAddress, realName, location) so birthDate is a natural fit. Full date rather than just birth year: birth year alone has up to ~12 months of imprecision at age boundaries, which could misclassify a 17-year-old as 18 or vice versa.