 Recommendation-track specifications that are subject to testing and PR review are:
        </p>
        <ol>
            <li>EPUB Reading Systems 3.3 [[epub-rs-33]]</li>
            <li>EPUB 3.3 [[epub-33]]</li>
            <li>EPUB Accessibility 1.1 [[epub-a11y-11]]</li>
        </ol>
    </section>
    <section id="sotd">
    </section>

    <section>
        <h1 id="introduction">Introduction</h1>
        <p>
          At the core, an EPUB 3.3 publication consists of a number of [=publication res