ref>
  <emu-xref href="#sec-additional-syntax" title></emu-xref>

  <!-- refs to imported biblio clause -->
  <emu-xref href="#sec-foo">with link text</emu-xref>
  <emu-xref href="#sec-foo"></emu-xref>
  <emu-xref href="#sec-foo" title></emu-xref>

  <!-- refs to local nonterminal -->
  <emu-xref href="#prod-TestProduction"></emu-xref>
  <emu-xref href="#prod-TestProduction">with link text</emu-xref>

  <!-- refs to ES6 nonterminal -->
  <emu-xref href="#prod-PrimaryExpression"></emu-xref>

  <!-- refs to l