Linux

Just realized that even if there is no mechanism to get the exact date from any of these age tracking systems, they'll be able to infer the exact dates by just looking at when the user/device transitions to the next bracket. Then they'll know the birthday for the start of that bracket falls somewhere between the last check and the current one.

Though maybe that data can be poisoned by making it transition backwards occasionally, so it looks like the user is editing their age older and back or something. But, on the other hand, a lack of data or poisoned data is going to be a flag on its own at some point (if not already).