The "kebab-case" classname of the emitter that raised the event.
Frame is represented as iframe.
The type of event that was raised. Equal to the typename of the event payload in "kebab case".
Guaranteed to be unique within each topic, but can be repeated between topics (e.g. WebContentsEvents.CrashedEvent and ApplicationEvents.CrashedEvent).
A general will-move or will-resize event without event type.