e>
    <slot></slot>
  </template>
  <div class="wrapper">
    <button style="order: 2" id="a1">Item A</button>
    <button style="order: 1" id="b1">Item B</button>
    <button style="order: 3" id="c1">Item C</button>
  </div>
</span>
<br>

<span id="host2" class="test-case" data-expect="b2,a2,c2"
      data-description="Slot is a grid with reading-flow.">
  <template shadowrootmode="open">
    <style>
    .wrapper {
      display: grid;
      reading-flow: grid-order;
    }
    </style>
    <slot class="wr