The full path of the nib file that stores the window associated with the receiver.
- macOS 10.0+
init was used to initialize the instance, this property contains the path. If
init was used,
window locates the nib in the file’s owner’s class’ bundle or in the application’s main bundle and returns the full path (or
nil if it cannot be located). Subclasses can override this behavior to augment the search behavior, but probably ought to call