Apple wants everyone to collaborate a technology that will sit above metal, Direct3D, and Vulcan that talks down to those disparate technologies. They provided a sample to show possibilities that they said they don't expect to be the standard. https://webkit.org/blog/7380/n...
Relevant quotes to dispel the paranoid ramblings posted by others.
"In order to expose a modern, low-level technology that can accelerate graphics and computation, we need to design an API that can be implemented on top of many systems, including those mentioned above."
"We don’t expect this to become the actual API that ends up in the standard, and maybe not even the one that the Community Group decides to start with, but we think there is a lot of value in working code."