No, it’s whoever makes the computer, and their suppliers - they design the board, take the chip from Intel, select how it’s wired up and which other components are added - and they write/modify/test the firmware and drivers for Windows, and then they ship it. Any knowledge about how to make their particular design work with Linux isn’t tested, documented or shared. The fact that Linux doesn’t have “one” version which everyone can say “support and test this, or I won’t buy your hardware” means that it’s much harder for vendors to justify spending time/money on any one Linux version (Ubuntu, RedHat, Endless, whatever). So most don’t bother. Not supporting any Linux doesn’t prevent them from selling their devices, so why would they?