Social login
Also called: OAuth login, Sign in with Apple, Sign in with Google
Signing in through another provider, like Sign in with Apple or Continue with Google.
Definition
The app asks an identity provider to vouch for the user instead of handling a password. Testers check first-time vs returning users, canceled consent, hidden emails (Apple relay addresses) and linking with an existing email account.
In practice
A user who signed up with email and later taps "Continue with Google" using the same address should land in the same account, not a new empty one.