Identifies if the tag is orphaned or not. 
   Namespace:   Autodesk.Revit.DB  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 18.0.0.0 (18.2.0.0) 
Syntax
Remarks
 Orphaned tags are those tags that are associated with an instance of a linked Revit file but have no host element. Tags become orphaned when the element they were tagging was deleted from the link.