Sure it uses Wine, but the Direct3D API is handled by the proprietary D3DMetal framework, which implements Direct3D on top of Metal. This is different than CodeWeaver's CrossOver approach, which uses Wine's DirectX-on-Vulkan implementation and then MoltenVK to run Vulkan on Metal.
So, it is not just Wine. It is Wine plus a large proprietary Apple Framework that has most of the Direct3D magic sauce.
Thanks for the info! I think a couple of us in this thread may be arguing cross purposes - I want to ensure that codeweavers gets credit for their open source contributions and you want to ensure technical accuracy. These are both good goals and don’t conflict with each other.
I imagine it’s simply a proprietary product based on liberally licensed (LGPL) open source code, much in the same way Safari was built upon KHTML.