hook_frontpage.php

<?php
/**
 * Hook to add the aggregator2 lik to the frontpage.
 *
 * @param array &$links The links on the frontpage, split into sections.
 */
function aggregator2_hook_frontpage(&$links) {
    assert('is_array($links)');
    assert('array_key_exists("links", $links)');

    $links['federation'][] = array(
        'href' => SimpleSAML_Module::getModuleURL('aggregator2/'),
        'text' => '{aggregator2:aggregator:frontpage_link}',
    );

}