source_ property
Source is which lane produced it: git (built from the repo) or image (an already-built ref deployed as-is, including promote and rollback).
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? source_;