message property
Message is the chain's own explanation, e.g. "execution reverted". It is "upstream unavailable" when the deployment minted the error rather than the chain — that is the one message this side writes.
Please note: This property should have been non-nullable! Since the specification file does not include a default value (using the "default:" property), however, the generated source code must fall back to having a nullable type. Consider adding a "default:" property in the specification file to hide this note.
Implementation
String? message;