version property
Version is the playbook's own name for this edition of its content, chosen by whoever authored it. It travels onto every journey projected from it. The store's numeric revision is a separate value and lives beside it.
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? version;