The kernel uses a patch-based workflow. Someone sends a bunch of patches to a list, gets feedback, improves on the patches, and sends the new set of patches. This might have added patches to the set, or changes to the existing patches. Repository write access is not (generally) shared between developers.
This is a very, very different way of using git from how almost everyone else uses git.
This is a very, very different way of using git from how almost everyone else uses git.