This is the Rn — just the last path segment — naming this specific stage row under its parent FSM object's Dn. For this chassis slot endpoint's FSM tracking, this Rn is built from a sequence number, so it's what distinguishes this one stage from the several other stage rows the same workflow run generates as it progresses step by step. A typical Rn value here looks like 'fsm-stage-3', identifying this as that specific numbered stage rather than the workflow's first or last step.