The purpose of this module is to give you a fine-grained control over a URL's
query-string in Varnish Cache. It's possible to remove the query-string,
clean it, sort its parameters or filter it to only keep a subset of them.

This can greatly improve your hit ratio and efficiency with Varnish, because
by default two URLs with the same path but different query-strings are also
different. This is what the RFCs mandate but probably not what you usually
want for your web site or application.