core + attic (Attic Area): these terms have been either deprecated from the core or extentions, or removed from pending as not accepted into the full vocabulary.

additionalNumberOfGuests

Canonical URL: http://schema.org/additionalNumberOfGuests

Thing > Property > additionalNumberOfGuests

If responding yes, the number of guests who will attend in addition to the invitee.
Values expected to be one of these types
Number
Used on these types
RsvpAction

Schema Version 3.3