Packaging : What files are stripped out?

I’m creating a plugin and while trying to think of a data architecture I have to make sure that I know the rules to what files exactly get removed for packaging.

I know that editor modules get stripped out, of course.

Now, I’m doing a custom editor and I’m not sure about graphs.
EdGraph, EdGraphNode and the likes are obviously editor classes, but they reside in the Engine package and therefore I believe they should not be stripped out for packaging, is that correct?

Is it safe to build data architectures based on those classes? I suppose it has to because after all, animation graphs, behavior trees etc. still have to function in packaged games, but I have to make triple sure in order to not waste hundreds of hours of development time.