This is the object's relative name (Rn) — just the last path segment of its Dn, the piece this DefinitionDelTask instance contributes to its own address within the MIT tree. Deleting a QoS definition isn't instantaneous — UCS Manager has to unwind every reference to it on every fabric interconnect and adapter that used it, and this task object is what tracks that cleanup to completion. For this kind of object the Rn is typically built from the same identifying value as its Dn's final segment, e.g. the tail end of `org-root/ep-qos-def-gold-video/del-task`, so two sibling instances never end up with colliding addresses under the same parent.