not-os

kernel

$ nix-build -A kernel
/nix/store/igdd4pi4jb5d6l1yf01fdm13ndw89x3w-linux-4.14.84

The kernel derivation results in an actual kernel, a bzImage file, but also in a set of kernel modules.

The modules are packaged in the shrunk derivation, which itself is used to create the initrd.