NSDocument.ChangeType.changeReadOtherContents
The document has been initialized with the contents of a file or file package other than the one whose location is in the fileURL property, and therefore can’t possibly be synchronized with its persistent representation.
Declaration
case changeReadOtherContentsDiscussion
For example, init(for:withContentsOf:ofType:) passes this value when the two passed-in URLs are not equal to indicate that an autosaved document is being reopened.