,
     in which case they
     <a href="terminology.html#must-requirement" id="must-requirement_xref55">must</a>
     not have an end tag.</li>
     <li>SVG and MathML elements whose start tag is
     <a href="syntax.html#syntax-self-closing" id="syntax-self-closing_xref2">marked as self-closing</a>,
     can&#8217;t have any contents.</li>
     <li>The contents of an SVG or MathML element whose start tag is not
     <a href="syntax.html#syntax-self-closing" id="syntax-self-closing_xref3">marked as self-clo