Lets authentication plugins trigger the creation of users if the plugin can authenticate them.
If an authentication plugin thinks that a user should be able to log in, and furthermore thinks that it is able/allowed to automatically create user accounts, then it is now able to do just that. The authentication API now has a new method - can_auto_create_users() - to define whether each authentication instance feels it can/should be able to do this. If the instance thinks it can, it needs to export some information through the get_user_info method in order to populate the user account. Although this may change shortly to be optional, with the users instead being forced to enter any information that is required that they haven't otherwise filled out.