On this tab, you are either creating a new role or editing an existing one. The following properties can be set:
•Role display name - name of the role that will be used on the live site and in the administration interface
•Role code name - name of the role used in your code
•Role description - text description of the role
•Can manage the group - indicates if members of the role can manage the group by means of the Group profile web part
More resources can be found at Developer's Guide -> Modules -> Groups -> Overview.