Microsoft has published a repository with its modifications for the Linux kernel
Microsoft has published all changes and additions to the Linux kernel used in the kernel provided for the WSL 2 (Windows Subsystem for Linux v2) subsystem. The second edition of WSL features a complete Linux kernel instead of an emulator that dynamically translates Linux system calls into Windows system calls. The availability of the source code allows enthusiasts to create their own builds of the Linux kernel if desired.
