Microsoft has announced that it's working with Collabora to develop mapping layers for OpenCL and OpenGL in Direct3D 12 (D3D12). The work is building off of Microsoft's previous works on mapping layers, such as D3D11On12 and D3D9On12, plus the D3D12 Transition Layer library, but targets the popular open-source libraries.
To do this, Microsoft and Collabora will be using the Mesa 3D open source project, an implementation of multiple graphics APIs. The companies will be adding a D3D12 backend to the Mesa project to add support for OpenCL and OpenGL, starting with versions 1.2 and 3.3, respectively.
The main reason for this is that not every machine and component has great native support for OpenCL and OpenGL, and the mapping layers will improve compatibility. The main focus is to improve compatibility with productivity and creative apps, rather than games. Microsoft also aims to help developers port their apps to D3D12, specifically those using old versions of OpenCL and OpenGL. The mapping layers should provide some help on how to use the D3D12 Transition Layer library to migrate the app to Microsoft's API. Microsoft also hopes that the graphics development community will benefit from the contribution of the D3D12 backend to the Mesa project.
If you're interested in the project, you can follow the work in progress on GitLab. You can also learn more about the goals of the project on Collabora's announcement, which is more technical than Microsoft's.