This API is provided by plugin.changeMetadata() and provides interface for customization and data updates of change metadata.
onLabelsChanged
changeMetadataApi.onLabelsChanged(callback)
Params
- 
callback function that’s executed when labels changed on the server. Callback receives labels with scores applied to the change, map of the label names to LabelInfo entries 
Returns
- 
GrChangeMetadataApifor chaining.