OptionalexpiresWhen the entitlement lapses, in epoch milliseconds; null (or absent) means it never expires.
OptionalquantityHow many units the grant confers; a positive integer when present (validated at submit).
OptionalsourceWhere the grant came from (a promotion, a bundle), recorded on the grant for the audit trail.
OptionalversionThe grant's version, for hosts that version their item definitions.
Optional details on an entitlement grant (a user owning an item or feature).