https://www.cnbc.com/2018/03/20/how-to-see-which-facebook-apps-have-access-to-your-data.html

If you've ever opened an app and selected the option to "log in with Facebook" instead of creating a new account, chances are that the people or company behind that app know a lot about you.

According to Facebook, each app that you log into will get your gender, networks you belong to, username, your user ID, your full name and your profile picture. They also get access to your full friends list and any other public information on your profile.