This is the object's Rn — the Relative Name, i.e. just the last path segment that the physical endpoint contributes under its parent's Dn. For this blade's physical port into the chassis backplane fabric, the Rn is the naming component (built from things like chassis id, slot id or port id) that distinguishes this specific row from its siblings under the same parent container in the tree. A typical Rn here looks like 'port-1', which is appended to the parent chassis/blade Dn to form the full path.