"background-color: rgb(14, 138, 22); color: rgb(0, 0, 0);" aria-label="GitHub label: Closed Accepted by DTCG Resolution">Closed Accepted by DTCG Resolution</a></span></div><div class="">
    Are token types optional or required?
  </div></div>

  </section><section id="extensions"><div class="header-wrapper"><h3 id="x5-5-extensions"><bdi class="secno">5.5 </bdi>Extensions</h3><a class="self-link" href="#extensions" aria-label="Permalink for Section 5.5"></a></div>
  <p>The <strong>extensions</strong> proper