JetBrains.EnvDTE.Client by JetBrains

<PackageReference Include="JetBrains.EnvDTE.Client" Version="20220221.47.0" />

 ProjectItemKindModel

public enum ProjectItemKindModel
namespace JetBrains.Rider.Model { public enum ProjectItemKindModel { Unknown, PhysicalFile, PhysicalFolder, Project, VirtualDirectory } }