You may optionally specify a PHP callback here in order to fetch more data or alter the controller response for your page.<br />
<br />
Callback arguments:
<ol>
	<li><code>\XF\Pub\Controller\AbstractController $controller</code><br />The controller instance. From this you can inspect the request, response etc.</li>
	<li><code>\XF\Mvc\Reply\AbstractReply &$reply</code><br />The standard reply from the page controller.</li>
</ol>