The maximum virtual attendee capacity of an [Event](https://schema.org/Event) whose [eventAttendanceMode](https://schema.org/eventAttendanceMode) is [OnlineEventAttendanceMode](https://schema.org/OnlineEventAttendanceMode) (or the online aspects, in the case of a [MixedEventAttendanceMode](https://schema.org/MixedEventAttendanceMode)).