nt to `application/activity+json`.
        </p>

    </section>

  </section>

  <section>

    <h2>Conformance</h2>

    <p>
      All diagrams, examples, and notes in this specification are
      non-normative, as are all sections explicitly marked non-normative.
      Everything else in this specification is normative.
    </p>

    <section>

      <h3>Documents</h3>

      <p>
        Conforming documents are those that comply with all the conformance
        criteria for documents. For readability, so