Meta is set to limit time teens can spend on Meta and Facebook -- but how do you confirm someone's age?

Meta's landmark settlement with nearly every U.S. state promises curfews and time limits for teens on Instagram and Facebook—but rests on age and parent checks nobody has figured out how to make work.

The deal, which ended a federal trial in Oakland, California, on Wednesday, gives Meta one year to identify which of its users are 13 to 17 years old.

Those accounts will have curfews and time limits switched on by default, and only parents will be allowed to loosen them.

How that gets enforced is unclear—and any system Meta builds risks angering privacy advocates, who warn it hands platforms and governments yet another way to identify users, infringing on civil liberties.