This is how an integration with Facebook OAuth 2.0 authentication would work.
First, a user creates an application in https://developers.facebook.com/. Their Facebook application App ID and App Secret must be loaded in the 'Basic' tab in the Client ID and Client Secret fields, respectively.
In the Facebook application Settings → Advanced menu, they must enter their Thinfinity Remote Desktop Server URL: "https://<ThinfinityRDServer>/oauth2" in the “Valid OAuth redirect URIs” under the “Client OAuth Settings” title.
Then in the 'Server' tab, they must indicate that the Server Kind is 'Custom' and the fill in the rest of the values like this:
Authorization URL: https://www.facebook.com/dialog/oauth
Other Keys: scope=email
Token Validation URL: https://graph.facebook.com/oauth/access_token
Profile Information URL: https://graph.facebook.com/me?fields=email
Login Username value in returned JSON: email
Finally, in the 'Mapping' tab, they must match the emails of the users that will be validated with Facebook with their corresponding Windows user for Thinfinity Remote Desktop Server.