Hi Florence,
I asked our support team and they sent me this text mode to try to show the ID of the user, but it won't show the name or show outright their access level, but it's hopefully closer for you!
displayname=User GUID and Sharing
listdelimiter=<p>
listmethod=nested(accessRules).lists
textmode=true
type=iterate
valueexpression=CONCAT({accessorID}, " - ", {coreAction})
valueformat=HTML
Kyna