number property
Number is the issue's number on that board, from 1 and monotonic there. Unique per board, never across the org — so it addresses an issue only together with Project.
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
int? number;