UpgradeRestrictionSignal: StorageDescriptor<[], UpgradeRestriction | undefined, false>

An option which indicates if the relay-chain restricts signalling a validation code upgrade. In other words, if this is Some and [NewValidationCode] is Some then the produced candidate will be invalid.

This storage item is a mirror of the corresponding value for the current parachain from the relay-chain. This value is ephemeral which means it doesn't hit the storage. This value is set after the inherent.