assignee property
Assignee is who holds the work. EMPTY MEANS UNHELD, which is what makes the issue claimable: claiming one already held by someone else is refused with 409 rather than quietly taken.
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? assignee;