My grandma runs Linux on her desktop (I set her up with Fedora).
GitHub hosts lots of FLOSS, of course. The platform itself is fully proprietary, although apparently they plan to liberate some amount of the core. That's why snowdrift.coop choose gitlab.com, although even that's a compromise (we used to use their githost.io offering so we could stay on gitlab CE, but that service closed down and we had to weigh staying on fully-FLO tools vs network effects).
GitHub hosts lots of FLOSS, of course. The platform itself is fully proprietary, although apparently they plan to liberate some amount of the core. That's why snowdrift.coop choose gitlab.com, although even that's a compromise (we used to use their githost.io offering so we could stay on gitlab CE, but that service closed down and we had to weigh staying on fully-FLO tools vs network effects).