Rewriting

Rewriting is a convenient method of moving an entire tree

<rewriteSystem systemIdStartString="http://www.w3.org/"
               rewritePrefix="/projects/w3c/WWW/"/>

This entry would map:

http://www.w3.org/2002/xmlspec/dtd/2.3/xmlspec.dtd

to

/projects/w3c/WWW/2002/xmlspec/dtd/2.3/xmlspec.dtd