I might be sort off cached
// Get the associative array representing the xml.
if ($user_info['is_guest'] && !empty($modSettings['cache_enable']) && $modSettings['cache_enable'] >= 2)
$xml = cache_get_data('xmlfeed-' . $xml_format . ':' . md5(serialize($_GET)), 240);
if (empty($xml))
{
$xml = $subActions[$_GET['sa']][0]($xml_format);
if ($user_info['is_guest'] && !empty($modSettings['cache_enable']) && $modSettings['cache_enable'] >= 2)
cache_put_data('xmlfeed-' . $xml_format . ':' . md5(serialize($_GET)), $xml, 240);
}