So what? Did Broadcom or Nvidia contribute to the open source drivers you probably use on Linux? How many contributions did Intel make to the Linux kernel from 1991 to 2000 during which the kernel was in the infancy of running on Intel silicon?

Do Intel's micro-arch manuals tell the whole story or do people go to Anger Fog website frequently (https://www.agner.org/optimize/)?

It doesn't matter.