Linux kernel development happens on Git. In fact, Git was created for the Linux kernel. Maybe instead of Git you mean GitHub? I can't find a link now, but if I remember right there was a brief period when Linux kernel development had to move to GitHub. Maybe when kernel.org got hacked? Linus Torvalds didn't like the way that GitHub formatted merge commits [1] (from a later date, but I think it was the same issue).

[1] https://lore.kernel.org/lkml/CAHk-=wjbtip559HcMG9VQLGPmkurh5...