The designator ancestor describes all notes in a direct line of descent from the cover to the current note. Also, if there are siblings at the top level, it may be to the root note for the section of the hierarchy containing the current note. From v5.8.0,deprecated in favour of ancestors.
Designators don't allow offset references as with attributes. Thus $Name("Some note") works but children("Some note") doesn't. If an offset designator is needed use find() instead.