In a blog post on Windows Subsystem for Linux Microsoft accidentally leaked details about the next major version of Windows 10.
That will not be Windows 10 20H2 of course, which is going to be a minor update, but Windows 10 21H1, which we now know will be called the Iron (Fe) branch.
Support for DxCore, D3D12, DirectML and NVIDIA CUDA is coming to a Windows Insider Fast build soon. The Fast ring is currently on our Manganese (Mn) OS branch. We expect the Fast ring to switch over to our Iron (Fe) branch toward the later part of June which will expose this new functionality to Insiders.
The post suggests Insiders will soon start working on Windows 10 21H1, which is expected to bring a number of new features, including Win32 containers and cosmetic improvements to the OS.