diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index 442b125657..e39d5ee13e 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -4756,6 +4756,20 @@ function page_header($page_title = '', $display_online_list = true, $item_id = 0
 	// A listener can set this variable to `true` when it overrides this function
 	$page_header_override = false;
 
+	/**
+	* Execute code and/or overwrite  page_header()
+	*
+	* @event core.page_header
+	* @var	string	page_title			Page title
+	* @var	bool	display_online_list		Do we display online users list
+	* @var	string	item				Restrict online users to a certain
+	*									session item, e.g. forum for
+	*									session_forum_id
+	* @var	int		item_id				Restrict online users to item id
+	* @var	bool	page_header_override	Shall we return instead of running
+	*										the rest of page_header()
+	* @since 3.1-A1
+	*/
 	$vars = array('page_title', 'display_online_list', 'item_id', 'item', 'page_header_override');
 	extract($phpbb_dispatcher->trigger_event('core.page_header', compact($vars)));