The binding that triggered the retrain.
OptionalchallengerThe newly-trained challenger model + run (present only when retrained).
OptionalcomparisonChallenger-vs-incumbent comparison (present only when retrained).
The incumbent model that was found stale.
Whether a retrain actually ran (false when the model was not stale).
Why the incumbent was found stale (empty when not stale).
The outcome of a retraining trigger for a single stale binding/model.