<PackageReference Include="Microsoft.Win32.Registry" Version="5.0.0-preview.2.20160.6" />

Microsoft.Win32.RegistryValueOptions

public enum RegistryValueOptions
Specifies optional behavior when retrieving name/value pairs from a registry key.
namespace Microsoft.Win32 { public enum RegistryValueOptions { None = 0, DoNotExpandEnvironmentNames = 1 } }