[ramesh31]

> I'm pretty sure they outsource/fund a fairly large amount of the work, the article mentions Igalia & from memory Codeweavers are largely responsible for Proton.

Userspace stuff for sure. But the drivers are mostly Valve.

[MegaDeKay]

Take a look at the PDF of the talk from the article. There are numerous examples of Igalia contributions to the kernel.

[idontknoworcare]

In 2008 they outsource all the kernel work I read