Can't see prefab children in project window

Unity Engine
,
1

I have an empty GameObject whose children are visible in the hierarchy.

6404226--714654--upload_2020-10-10_18-25-46.png

However, when I made it a prefab, I can’t see the child objects in project view mode.

6404226--714657--upload_2020-10-10_18-26-19.png

I want to be able to see an arrow on this prefab in the project window that lets me view the child objects, like this:

6404226--714660--upload_2020-10-10_18-27-37.png

What am I doing wrong?

To be clear, the child objects are there in the prefab, as when I drag it into the scene, they show up in the hierarchy.

6404226--714654--upload_2020-10-10_18-25-46.png

2

They removed that feature when nested prefabs was introduced.