menu.php

 * The elements in the array are :
 *     0: Menu item name
 *     1: Minimum level or capability required.
 *     2: The URL of the item's file
 *     3: Class
 *     4: ID
 *     5: Icon for top level menu
 
 * @global array $menu

menus.php

	/**
	 * Fires before the administration menu loads in the User Admin.
	 * The hook fires before menus and sub-menus are removed based on user privileges.
	 */
	do_action( '_user_admin_menu' );
	
	
	/**
	 * Fires before the administration menu loads in the admin.
	 * The hook fires before menus and sub-menus are removed based on user privileges.
	 */
	do_action( '_admin_menu' );
	



add_filter( 'custom_menu_order', '__return_true' );
$menu_order = apply_filters( 'menu_order', $menu_order );





	do_action( 'admin_page_access_denied' );
	wp_die( __('You do not have sufficient permissions to access this page.') );




	/**
	 * Filter administration menus array with classes added for top-level items.
	 *
	 * @since 2.7.0
	 *
	 * @param array $menu Associative array of administration menu items.
	 */
	return apply_filters( 'add_menu_classes', $menu );