Sometimes people have XHTML (or technically valid XML HTML but not really XHTML because it's not in a namespace) for the convenience of using XML tools, but they serve it as HTML for maximum compatibility. When itstool serves freshly translated XML/HTML/XHTML, it (or rather libxml2) minimizes empty elements, like this:
Correct XML. Danging opening tag in non-XML HTML.
We should be able to disable tag minimizations and do whatever other tricks make compatibility work better, while still creating XML.