On servers especially, phantomjs2 pulls graphical dependencies which is unecessary. This pathes enable the package to be linked/installed without phantomjs2. Phantomjs2 is disabled by default since it has been deprecated in grafana https://grafana.com/docs/grafana/latest/guides/whats-new-in-v6-4/
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.