SQL Server Audit Action Group:
DATABASE_PERMISSION_CHANGE_GROUP
This group tracks permission changes on a database itself as opposed to permission changes on objects within that database. If you enable this group in a server audit specification, it will track permission changes on all databases within that SQL Server instance. If you enable this group in a database audit specification, it will only check permission changes on that particular database.
LOGbinder for SQL Server
events generated under this
Audit Action Group: