URL of an MSH

Line 1002 in section 8.5.2.1.2 (of Message Services Specification,
Version 1, 11 May 2001) discussses the TraceHeader/Sender/Location
element, and says that it contains "the URL of the Message Service
Handler".

I was somewhat surprised when I read this.  This is the first time
anybody implied that every MSH has a URL.  Is it even clear that all
communication protocol addresses are URL's?  There has been discussion
in the mail about using MQSeries as a communication protocol: what URL
would you use in this case?

(The MQSeries Java level actually does have a concept of URL's with
the scheme "queue".  Examples: "queue://qmname/qname" or
"queue://qmname/qname?prop1=val1,prop2=val2" where "qmname" is the
name of the MQSeries queue manager.  As far as I know this is only at
the Java level, not the core of MQSeries.  And I don't think "queue"
is an official scheme -- there's no RFC for it, as per RFC2717.)