Valve contractor Joshua Ashton, who originally created the Direct3D9 to Vulkan layer D9VK which was eventually merged with DXVK, is now working to help VKD3D-Proton for Direct3D 12 to Vulkan.
If you didn't understand much of that: DXVK and VKD3D-Proton translate Windows games' Direct3D calls into Vulkan so that they can work on Linux with the Wine compatibility layer which is all part of Steam Play Proton.
Ashton wrote up a blog post detailing all the work they've been doing, which has recently involved getting the APITrace tool hooked up and working with Direct3D 12. Ashton mentions that the work "may be useful for people who are developing games or working on implementing a D3D12 driver or translation layer for debugging purposes" and that the primary use here is to aid the VKD3D-Proton translation layer.
Speaking to Ashton myself last night to clear up some things including this being funded by Valve, Ashton mentioned how "debugging games these days is hard because of anti cheat and drm" and that this will enable developers to record the API calls. This means those calls can be debugged, enabling them to inspect everything and then play it back with VKD3D-Proton to see where it crashes so they can fix the Vulkan translation.
The blog post mentions that so far they've seen success with some big games like Ghostrunner, Resident Evil 2, Horizon Zero Dawn, Assassin's Creed Valhalla, Control working with the APITrace work.
Full blog post can be seen here for those interested.