Thanks for your answer Aryan! I am changing the nav order in page.php (core), and need to add the content there. However, your approach seems not to give me the onclick. I am using now:
$qa_content['navigation']['main']['tag']=array(
'url' => '
http://mycustomlink.com/',// qa_path_html('tags'),
'label' => 'my custom link', //qa_lang_html('main/nav_tags'),
'target' => 'blank',
'onclick' => 'console.log("test")',
);
onclick does not appear. Any idea?