
The standard attrsOf is strict in its *values*, meaning it's impossible to access only one attribute value without evaluating all others as well. lazyAttrsOf is a version that doesn't have that problem, at the expense of conditional definitions not properly working anymore.
To build the manual, you need Nix installed on your system (no need for NixOS). To install Nix, follow the instructions at https://nixos.org/nix/download.html When you have Nix on your system, in the root directory of the project (i.e., `nixpkgs`), run: nix-build nixos/release.nix -A manual.x86_64-linux When this command successfully finishes, it will tell you where the manual got generated.