OptionalauthOptionalclientFallback URL for the client app (used when no redirectTo is present). Optional.
OptionalendOverride GitHub's end-session endpoint. When omitted, the provider redirects directly to postLogoutRedirectUri.
OptionalsessionCookie / session domain used to validate redirect URLs (e.g. ".example.com"). Optional.
URL of the auth-callback page (used to build the post-login redirect). Optional.