Changes

<cd:constant type="yes">expands the xml reference to actual content for title and bookmark (<code>\xmlatt {xml:name::4}{title} </code> → <code>First section)</code>, see TUC file.  To expand userdata also use <code>\normalexpanded{\startsection[title=\xmlatt{#1}{title}]} </code> instead of <code>expansion=yes</code>.  <code>\normalexpanded{} </code> and are not in conflict, so you can use both.</cd:constant>

<cd:description><!-- To headings is associated the long description text, i.e. the content of the heading, but can also be associated numbers. These data can be processed for typesetting : * add a dot between the text and the number,* add a generic text before the "pure text"* appearance can be different for the text if we use it in the headers / footers, or in the Table of Content.* add vertical spaces before or after the text* add rules before or after the whole section under the heading* select if the command goes here -->title should appear on a right or a left page.