public sealed class Sandbox.SelectionBaseAttribute : System.Attribute

Apply this attribute to a component class to mark its GameObject as a selection base for Scene View picking. For example, if you click on a child object within a Prefab, the root of the Prefab is selected by default. With the SelectionBase attribute, you can designate a specific component (and its GameObject) to be treated as a selection base, ensuring it is picked when clicking in the Scene View.