Which country/state/region? Does it even apply? We're talking about an open source project that is not being sold, with contributors from all over the world.
The laws which any contributors to the OSS project are subject to. Some projects geographically restrict who can contribute to avoid issues like this, but when laws are passed by a jurisdiction in which existing maintainers reside those maintainers have the choice to either comply or move to a different jurisdiction. Moving is extremely disruptive & expensive, so they often comply.
IIRC laws in some US states will require OS's to collect the age of the user so services can age restrict, it does not mandate any kind of ID verification.
It doesn't matter it's an open source project, ultimately it ends up in commercial products which do require following the rules.