The niladic system function ŒEVT is valid only when you are running a ŒWE callback function in response to an event. It returns a scalar object reference, which is a reference to the object which generated the event. For example, if a callback is running in response to a Click event for a .Net Button object, ŒEVT will contain a reference to the Button.
If no event target is available, it will return a reference to the Null object.