There is an ongoing effort to “modernize” the kernel-development process;
so far, the focus has been on providing better
tools that can streamline the usual email-based workflow. But that
“email-based” part has proven to be problematic for some potential
contributors, especially those who might want to simply submit a small bug
fix and are not interested in getting set up with that workflow. The
project-hosting “forge” sites, like GitHub and GitLab, provide a nearly
frictionless path for these kinds of one-off contributions, but they do
not mesh well—at all, really—with most of mainline kernel development.
There is some ongoing work that may change all of that, however.

Source: LWN.net – [$] Pulling GitHub into the kernel process