netfx

What is NetFx in the Windows SDK?

What is NetFx, in the context of the Windows SDK? What differentiates NetFx tools from the tools in the regular SDK bin directory? I noticed that the version of sgen.exe in C:\Program Files\Microsoft SDKs\Windows\v7.0A\bin\ was built against .NET 2.0, but the version in C:\Program Files\Microsoft SDKs\Windows\v7.0A\bin\NETFX 4.0 Tools\ ...