Single sign-on
One switch. With it on, a visitor already signed in to another app on this account arrives here signed in, and a session started here carries to the others.
Turning this on adds the beacon host to the served page. The app then asks the account's shared host whether a session exists, and adopts it without a round trip through a login screen. Off is the safe default: an app that should keep its own sign-ins separate leaves it off.
Social sign-in providers are configured on the Sign-in tab and are not affected by this switch.
This app still carries the old redirect pair
callbackURL is read by nothing. redirectURL is still live: while it is set, an anonymous visitor landing on the login page is sent straight off this app to that address. Remove it here, then Save.