Delegated mouseenter and mouseleave events are reported as mouseover and mouseout in event type property.

For example:

$(document).delegate('div', 'mouseenter mouseleave', function(ev){
    console.log(ev.type);
});

reports mouseover and mouseleave;

The same with 'hover' alias that is said to be mapped to mouseenter and mouseleave.

This behaviour should be documented or fixed as it is confusing for developers that want to check the type of delegated events.