number property
Number is the posting key every voucher leg, rule and report references — stable, and the reason the chart is a fixed value rather than a table anybody can edit. It looks numeric and is a string: "1000" sorts and compares as text.
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? number;