+<!--
+
+### New filters:
+
+New virt_db-alike that does inteligent peer choice, explain merging,
+adds FD&N to explain. Keeps init responses (like "virt_db Classic"),
+makes routing choices based on local explain knowledge. Ref IDDI
+paper.
+
+Filter to convert Explain Classic to ZeeRex.
+
+CQL2PQF (which needs augmented ZeeRex) - MARC for Talis.
+
+SRU2Z39.50 (ditto).
+
+Figure out what additional information we need in:
+ ZeeRex (check against D3.1)
+ Init request (e.g. loop detection)
+ Query package (e.g. number of hops)
+ Query response (e.g. record source)
+
+-->
+