Proxy verifiers differ from a standard verifier or 3rd party OAuth2 logins as they depend on a proxy inbetween the Torus Network and the third party (Google).
This is often a login service provider such as Auth0, AWS Cognito, or Okta, and the login flow differentiates as below:
This causes these logins to have an additional trust assumption with the proxy as well, on top of the original flow. For integrations involving a proxy, we highly recommend DApps to inform users a third-party authenticator is present by including the line “Note: The following sign-in involves a third party authenticator: (list the logins) Linkedin, Twitter. etc”.