what’s for Engine project in VS solution when editing custom C++ class?
is it buildable? is it possible to use somehow?
If you’re using the source version then it’s editable and buildable.
If you’re using the launcher version it’s there for reference and debugging. You can easily check out the header files or code for things and if you have a crash you get a full stack trace. You won’t be able to rebuild it though.
If you want to build the engine you’ll need to link your github account and download the source. There’s more info here: A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums