FC Site
This basically contains all the sites from your FC Account, including the ones from where you're a team member and has access to.
Users with FC User role can login to the site directly from FC Site records. System will check for a user with matching email on that instance and, if found, log them into that account.
In case if account is not found, a new account will be created with the user details and assigned System Manager role and then log them in.
Users with FC Admin role can fetch the users on that instance. Filters specified in FC Settings will be applied. They also have the option to disable those users.
Certain instances might not require these functions, and in such cases, Login Restricted checkbox can be enabled, which will restrict all the above actions!