Diagram: Add ability to only show ancestor or descendant relationships

Ooh I like this idea. Thank you for suggesting it. I am wondering about the language. Ancestors and descendants is not all the Drupally. Ancestors and descendants implies causality or family tree like relationships that may not be accurate. I am wondering if either
A) 'references' or 'referenced by'
B) direction incoming or outgoing
C) reference or reverse reference

I am kind of leaning toward B because it accurately describes what we are talking about, direction rather than lineage.