Behavior for xref format="ditamap"

I found in one of my transforms a template for handling the
    syntactically valid case of <xref href=""
    format="ditamap"/>. Is the processing expectation for this combo
    defined anywhere? The 1.2 spec (3.4.2.9) defines the
    format="ditamap" semantic solely in terms of topicref context, not
    covering the xref case. Therefore this instance seems to be
    indeterminate. A working solution might point to a first topic in
    the subject map, but if a working result is not expected,
    implementers just need to know that it is indeterminate.

    
-- 

      

        
 Don R. Day 

        
 DITA and XML Consultant, Learning by Wrote

          Co-Chair, OASIS
            DITA Technical Committee 

        

          
"Where is the wisdom we have lost in knowledge?

          
Where is the knowledge we have lost in information?"

          
--T.S. Eliot