The `clementine` package is actually released under Apache license, but requires the unfree `libspotify` package to build. Now `nixpkgs.clementine` points to the free derivation and `nixpkgs.clementineUnfree` has been introduced for the package bundled with spotify support. Fixes #38315
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.