This is this stage's numeric position in the sequence of steps the state machine executes. Pushing the policy out to the fabric happens as an ordered sequence of named steps, and this record is one of those steps — useful for telling whether a stuck rollout is stuck on the fabric-A push, the fabric-B push, or the final verify. Stage order 1 would be the first step attempted (e.g. resolving the policy against fabric A) and a higher number like 3 would be a later step such as final verification, so admins can tell how far a rollout got before stalling.