My guess is that's for xbox - because that would be the only current platform without Vulkan support left.

DX over Vulkan for non-windows is being worked on too, just not by Khronos:

https://github.com/disks86/VK9

https://github.com/doitsujin/dxvk

and VKD3D for DX12 on Wine

It’s for Windows Store.

Windows supports Vulkan but to get onto the Windows Store you can only use DX12.

Is anyone else miffed that the DX on VK projects all use different nomenclature? Its impossible to tell from the name dxvk or vkd3d what version it supports. If they were named VK9, VK11, AND VK12 respectively it would be obvious. Or any permutation of their names and that paradigm - VKDX9, VX9, etc.