 (such as accents, <code>.</code>, <code>?</code>, <code>!</code>, ...). This value is used on URLs, on <code>id</code> HTML attributes, etc.</li>
<li><code>item.label</code>, the label of the main heading of the content. Usually it's only defined for chapters (<code>Chapter XX</code>), parts (<code>Part XX</code>) and appendices (<code>Apendix XX</code>).</li>
<li><code>toc</code>, array with the table of contents of this element. It's empty for most of the content types  (<code>cover</code>, <code>license