PhetioObject

PhetioObject (from scenerystack/tandem) is the base that attaches a Tandem, an IOType, and PhET-iO metadata (phetioState, phetioReadOnly, …) to an instance. Property, Node, Screen, and many UI controls extend it transitively.

You almost never subclass or configure this for a SceneryStack app. It exists so PhET-iO can address and serialize objects. For why the layer is in the library at all, see PhET-iO and Instrumentation. For dispose lifecycle (useful outside PhET-iO), see Disposable.