In most deployment scenario, VO administrators are members of the VO.
This new feature is to provide a way to use a VOMS role to delegate the handling of group requests
(group membership requests, role assignment requests) scoped to a specific group to some VO users. The role name is configurable, with a sensible default ("Group-Manager").

Users with the role in the VO root group and in a given subgroup for which they are managers will receive notifications of incoming group membership requests and will have the rights to approve or reject these requests.