testing results</li>
      <li>All possible combinations of features</li>
    </ul>
    <p>
      Although we did not formally test interoperability, we required two or more independent implementations for all
      features in the specification and tested general interoperability at
      <a href="https://github.com/w3c/wot-testing/tree/main/events">plugfest events</a>.
    </p>

    <h2 id="h_systems"><a id="test-systems" name="test-systems">6. Systems</a></h2>
    <p>
      This section contains descript