chrome/common/extensions/docs/templates/private/property.html

<dt>
  <span class="variable">{{name}}</span>
  <span class="property">
    (
      {{?optional}}<span class="optional">optional</span>{{/}}
      {{+partials.variable_type}}
    )
  </span>
</dt>
{{?description}}<dd>
  {{{description}}}
</dd>{{/description}}
{{?array.is_object}}
  <h4>Properties of each item</h4>
  {{+partials.type @:array api:api}}
{{/array.is_object}}