From the abstract: > UEFI is a proprietary and closed-source operating system, with a codebase almost as large as the Linux kernel... And this kernel build is

From the abstract: > UEFI is a proprietary and closed-source operating system, with a codebase almost as large as the Linux kernel... And this kernel build is a trimmed-down one, removing functionality that isn't necessary to initialize the hardware and boot the full kernel.