One issue group addressed by its composite key — security by source=Security&category=…&pattern=…,
governance by source=Gov&signalType=…&reference=… — with its header aggregate plus the first page of the
agents it was found on and of the endpoints it was found on, most-affected first. Every row carries a preview of its
findings (instancesTruncated when there are more); page through the rest with groups/summary/instances.
Use pageSize to size both sections; page past them with groups/summary/agents and
groups/summary/endpoints. An invalid key combination is a 400; a key that matches no current issue in your
organization is a 404. Authenticate with an API key.