We need to get to a point where the XHTML5 is valid so that we can browse the results on Jenkins. Found a few remaining issues in the data, including combining diacritics detached from their original char, so I've added a Schematron rule for that. Fixed some XSLT bugs, and I'm now at a point where I think only novel errors from Stow are likely to be thrown up. Waiting for the long build process to complete now, to see the latest crop of errors.