Visual Studio project structure

I am having a dive into https://github.com/dotnet/samples/tree/main/core/hosting TLDR; of what the example does: Host .NET runtime from C++, interact with managed C# code from unmanaged C++ code Inside are - an example managed C# library project ("DotNetLib") - a native C++ project ("NativeHost"). Looking within Visual Studio though, I see "DotNetLib" (C# icon) and "NativeHost.vs" (C++ icon), while there is a further "NativeHost" (C# icon) Project in a virtual "build" folder What is that .vs project, why is there 3 projects in total, and why is the "NativeHost" a C# project?