What is the proper method for extending the Editor Engine?

Not sure why, but after adding this to my uproject file:

 {
     "Name": "MyCodeProjectEditor",
     "Type": "Editor",
     "LoadingPhase": "Default"
 }

I get this error when trying to generate new project files:

119576-untitled.png

Can’t tell what file needs to be unlocked :confused: Any ideas?