th>
  </p>
  <p>
    <math>
      <mn>X</mn>
      <mfrac class="testedElement">
        <mn>X</mn>
        <mo lspace="2em" rspace="0em">X</mo>
      </mfrac>
      <mn>X</mn>
    </math>
  </p>

  <!-- Only in-flow children affect determination of embellished operators. -->
  <p>
    <math>
      <mn class="oof1">0</mn><mn class="oof2">1</mn><mn class="nobox">2</mn>
      <mn>X</mn>
      <mn class="oof1">0</mn><mn class="oof2">1</mn><mn class="nobox">2</mn>
      <msub class="testedElement">
        <mn 