This event is signalled by AbstractMenu::getItems() (and it's children) in inc/Menu/AbstractMenu.php when when the menu in question is assembled, handlers can use it to add or remove items from the menu.

The $data array contains two keys:

• view defines the menu that is currently built (please refer to Menus on which menus exist)
• items contains an array of AbtractItem descendants.

The following plugins are known to handle this event and their source code may be a good start for understanding and implementing a handler yourself.

• Action Plugins
• Events
• Menus