<!-- Note that in HTML5 the boolean attribute absence represents false value,
     true otherwise. If it is present then the value must be empty or
     case-insensitively match the attribute's name. -->

<form method="post" enctype="multipart/form-data">
  <table id="submit" class="proplist">
    <tbody>
      <tr>
        <th>archive</th>
        <td>
          <input type="file"
                 name="archive"
                 accept=".tar.gz"
                 required=""/>
        </td>
      </tr>
      <tr>
        <th>sha256sum</th>
        <td><input type="text" name="sha256sum" required=""/></td>
      </tr>
    </tbody>
  </table>
  <table class="form-table">
    <tbody>
      <tr>
        <td id="submit-padding"/>
        <td><input type="submit" value="Submit"/></td>
      </tr>
    </tbody>
  </table>
</form>