-a tree. The xxx_close() function is not called when the first lookup is
-completed. If there are subsequent lookups of the same type that quote the same
-file name, xxx_open() isn't called; instead the cached handle is re-used.
+a tree. Traditionally, lookup_querystyle does not use this (just returning a
+dummy value, and doing the "open" work in the xxx_find() routine); but this is
+not enforced by the framework.
+
+The xxx_close() function is not called when the first lookup is completed. If
+there are subsequent lookups of the same type that quote the same file name,
+xxx_open() isn't called; instead the cached handle is re-used.