The custom args the listener was registered with.
The type of event which fired (event.type).
The path (from getItemPath) to the item the event fired on (domItemTarget, falling back to the item the listener is attached to when no domItemTarget was found).
The registered name of the listener which would have run locally.
What a forwarded event is packaged as in render-only mode. See retrieveListener, makeForwardingListener.