The website sends a request for age verification.
The app[1] on the user's device[2] forwards that request to the chip on the user's ID card. The user authorizes themselves with their 6 digit PIN stored on the card.
The chip produces a signed reply containing the following payload fields: `issuing_country:string` and `over_18:bool`
[1] https://github.com/Governikus/AusweisApp
[2] iPhone, Android, Windows, MacOS, Linux or FreeBSD