What is the difference between masterIdentifier and identifier attribute of DocumentReference resource?

Need to understand difference between masterIdentifier and identifier attribute of DocumentReference resource.

As far as I know msteridentifier is assign to a specific version of the document but identifier is independent of the version.

  • masterIdentifier is the identifier given by the authoring system to that version of the document.
  • identifier for for any other identifiers that are useful. Some of them might apply to all versions of the document. Local identifiers of the document would go here.