What is saved in the __ExternalActors__ Folder?

Okay, thank you. However these actors cannot be used as sources of a backup system then, I think. But that’s what I need. The subfolder structure of __ExternalActors__ is cryptic and it is not possible to copy one __ExternalActors__ folder to another project.

So I still wonder if there is a system to “backup” a complete actor with all it’s properties to disk making it possible to restore it’s state later? All at design time…