The organizer of the event. If the organizer is also an attendee, this is indicated with a separate entry in attendees with the organizer field set to True. To change the organizer, use the move operation. Read-only, except when importing an event.
Source of an event from which it was created; for example a web page, an email message or any document identifiable by an URL using HTTP/HTTPS protocol. Accessible only by the creator of the event.