Where does this information go?

          <!-- classification systems documented here -->
        ]]><!-- personography may be stashed here -->
        ]]><!-- document-level keywords applied here -->
      ]]><div type="editorial">
        <!-- contextual information for which TEI does not provide
             a place in header, including ographies and interpretive
             keywords; perhaps also annotations -->

Or, in a separate file altogether.

Encoding Contextual Information, slide 2 of 11