ActionCodeSettings Structure that contains the required continue/state URL with optional Android and iOS bundle identifiers.
 AdditionalUserInfo Object to hold IDP-specific data for the user if the provider is one of Facebook, Github, Google, Twitter, or Apple.
 Auth The entry point of the Firebase Authentication SDK.
 AuthProvider Use this class to obtain credential information from different auth providers that Firebase supports.
 FirebaseUser Represents a user's profile information in your Firebase project's user database.
 UserInfo Represents a collection of standard profile information for a user.
 UserMetadata Holds the user metadata for the current FirebaseUser