This may be one of the reasons Apple does not support Vulkan.

"Apple is not comfortable working under Khronos IP framework, because of dispute between Apple Legal & Khronos which is private. Can’t talk about the substance of this dispute. Can’t make any statement for Apple to agree to Khronos IP framework. So we’re discussing, what if we don’t fork? We can’t say whether we’re (Apple) happy with that."

Agenda / Minutes for GPU Web meeting 2019-12-09 https://docs.google.com/document/d/1F6ns6I3zs-2JL_dT9hOkX_25...