IIUC the new Ubuntu-on-Windows stuff is a different take, reusing some of Interix but diverging substantially from the old implementation.
EDIT Source[1]: "Over time these [Interix] subsystems were retired. However, since the Windows NT Kernel was architected to allow new subsystem environments, we were able to use the initial investments made in this area and broaden them to develop the Windows Subsystem for Linux."
EDIT Source[1]: "Over time these [Interix] subsystems were retired. However, since the Windows NT Kernel was architected to allow new subsystem environments, we were able to use the initial investments made in this area and broaden them to develop the Windows Subsystem for Linux."
[1] https://blogs.msdn.microsoft.com/wsl/2016/04/22/windows-subs...