public Map<String, Set<ObjectPermission.Type>> getUserGroupPermissions() {
        return userGroupPermissions;
    }
Returns a map of user group IDs to the set of permissions granted for
that user group. If no permissions are granted for a particular user
group, its ID will not be present as a key in the map. This map is
mutable, and changes to to this map will affect the permission set
directly.

@return
    A map of user IDs to the set of permissions granted for that user.
guacamole/src/main/java/org/apache/guacamole/rest/permission/APIPermissionSet.java