This module implements an XML diff producing XML output.  Both input and
output are DOM documents, as implemented by XML::LibXML.

The diff format used by XML::DifferenceMarkup is meant to be
human-readable (i.e.  simple, as opposed to short) - basically the diff
is a subset of the input trees, annotated with instruction element nodes
specifying how to convert the source tree to the target by inserting and
deleting nodes.  To prevent name colisions with input trees, all added
elements are in a namespace http://www.locus.cz/XML/DifferenceMarkup
(the diff will fail on input trees which already use that namespace).

WWW: http://search.cpan.org/dist/XML-DifferenceMarkup/