System-Defined Client Groups
Broker creates several system-defined client groups. You can make only limited changes to these groups:
You cannot modify any of their properties; that is, you cannot change the description, name, lifecycle or storage type for these client groups.
You cannot delete system-defined client groups, except for the eventLog client group.
You can modify the document types belonging to the can-publish, can-subscribe, log-publish, and log-acknowledge lists for system-defined client groups.