This read-only CucsEquipmentSystemIOControllerFsmStageName enum names, as a fixed internal identifier, exactly which numbered step of the IO controller's workflow this stage record represents (for example the backplane-port-discovery step versus the firmware-programming step). Knowing the specific stage name lets an admin recognize which part of a multi-stage operation is slow or failing without having to infer it purely from the free-text description. Seeing the same stage name repeat across many chassis' IOMs that are all stuck at once would point to a systemic issue with that particular step rather than one bad module.