The DocBook sources of NixOS' manual are in the nixos/doc/manual subdirectory of the Nixpkgs repository. You can quickly check your edits with the following: $ cd /path/to/nixpkgs $ nix-build nixos/release.nix -A manual.x86_64-linux If the build succeeds, the manual will be in ./result/share/doc/nixos/index.html.