@feld @mint @vhns I don't think Nintendo has ever released any source code for anything outside of some experimental operating system they made back in the mid 2000s.
https://www.gamedeveloper.com/game-platforms/inside-nintendo-s-es-open-source-operating-system
Bluecoat gave a bunch of network stack improvements years ago, the most significant before Netflix.
Dell/EMC has realized their mistake and is now working to upstream their changes so they don't have to run really old kernels. They have storage and NFS fixes.
Microsoft donates code and drivers to make it work efficiently under Hyper-V. Citrix did the same for Xen.
Intel does a lot, AMD does some, Nvidia/Mellanox does a good amount for network drivers