inconsistent between the one-and two-argument forms. Thoughts?
--[[smcv]]
+
+> I've applied the branch as-is, so this bug is [[done]].
+> `prune` is not an exported API so changing it would be ok..
+> I think required 2-argument would be better, but have not checked
+> all the call sites to see if the `$file` is available split out
+> as that would need. --[[Joey]]