Ha. I didn't even consider git itself being there. I know LT has done A LOT for FOSS, but I've always gotten the impression that he doesn't care that much about it. At least not in the Stallman sense.
I mirror the code I rely on and like, except for things that are just too large my servers get upset. Most of the code here is used by my own applications. I vendor most of my dependencies for this reason as well, but for other apps I just use this works. Speaking of which, I need to mirror more things!
https://git.vaughnnugent.com/cgit/
Funny enough I think, git itself has mostly migrated to GitHub. Can't speak for development, but all the documentation links back to GitHub.
Discussion
Yeah I find it hard to believe LT uses GitHub, or trusts it, but as far as the public facing resources go, they mostly point to GH in my recent experience.
Probably the low or free cost hosting incentives they have. Who knows. There's too much behind the scenes for me to keep up with. I'm bearish on FOSS repos being there though.