We’re also working with our ISV and IHV partners on future efforts, including bringing the lightweight runtime and tooling capabilities of the Xbox One Direct3D implementation to Windows, and identifying the next generation of advanced 3D graphics technologies.
Also, they point out that other graphics APIs such as OpenGL and Mantle aren't available on Xbox One,
With Xbox One we have also made significant enhancements to the implementation of Direct3D 11, especially in the area of runtime overhead. The result is a very streamlined, “close to metal” level of runtime performance. In conjunction with the third generation PIX performance tool for Xbox One, developers can use Direct3D 11 to unlock the full performance potential of the console.
which should have been obvious from the start, but they seem to have wanted to point out that they are using their own streamlined Direct3D implementation, which they apparently plan to bring to Windows, similar to what Mantle will do on Windows. That sounds pretty exciting. We could be dealing with a much lower level version of DirectX similar to Mantle that is optimized to take full advantage of both AMD and Nvidia GPUs on Windows. Competition is awesome.
We are very excited that with the launch of Xbox One, we can now bring the latest generation of Direct3D 11 to console. The Xbox One graphics API is “Direct3D 11.x” and the Xbox One hardware provides a superset of Direct3D 11.2 functionality. Other graphics APIs such as OpenGL and AMD’s Mantle are not available on Xbox One.