FIDO2 - Where do Android and IOS platform authenticators store private key credentials?

I’m new to FIDO2 specification.

I’m aware that Android and IOS devices support FIDO2 protocols (even Android phones could act as a physical key for FIDO2 authentication).

However, Could anyone let me know that, when we use the platform authenticators such as Android fingerprint, where are the credentials (private keys) stored?

Thanks.