Why does the RotationCube in HelloCube-Reparenting have Child components from the beginning

[00nico00]

When I was reproducing the HelloCube-Reparenting example, I directly right-clicked on the RotationCube to create a new child object, Cube. This parent-child relationship only exists within the UnityEditor and does not involve ECS Parent and Child components (originally, I thought this relationship would be automatically converted during baking). As a result, I encountered errors when reproducing it on my own (until I initialized attached as false). When I examined the scene of the official example, I noticed that the RotationCube comes with a Child Buffe. I would like to know how this was achieved.

[noble-shake]

Dynamic Buffer will automatically added.

https://docs.unity3d.com/Packages/com.unity.entities@1.0/api/Unity.Transforms.Child.html

Remarks
The ParentSystem automatically adds and manages this component and its contents. You can read this list, but you shouldn't add or remove buffer elements.

When an entity with this component is destroyed, the ParentSystem will automatically remove the Parent components from each child entity.