Can passkeys created in one user app on iOS be used by another one? For example, can an app create a passkey, which will be used by Safari for authentication?

Docs suggest that an identity consists of a private key packaged with the certificate that contains and vouches for the corresponding public key. Is it possible to create an identity backed by a private key generated in secure enclave?

Docs suggest that keychain items can be shared among apps within a keychain access group. Is it possible to share access to the key generated in Secure Enclave with a third-party app on macOS under the same login context?