source_ property
Source is the plane that reported the reading: "agent", "byo" or "visor" — the same vocabulary the board's rows carry, and what ?source= narrows on.
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_;