Apparently I don’t have it…
Don’t pay too much attention to it…
Many things in Unreal have been working for many years, do not change, but are considered experimental. 
Oops, my attentiveness seems to be failing me again. I thought that was the original problem…
If the project initially builds successfully in VS, but there is a failure during packaging - then most likely you are referencing from the runtime module to the editor module, which is not added when packaging the project (it should not be there). 
That is, you are trying to use a feature that is only intended while you are working with the project, but not when you are playing it.