Nixpkgs is a collection of packages for the Nix package manager. It is periodically built and tested by the Hydra build daemon as so-called channels. To get channel information via git, add nixpkgs-channels as a remote:

% git remote add channels https://github.com/NixOS/nixpkgs-channels.git

For stability and maximum binary package support, it is recommended to maintain custom changes on top of one of the channels, e.g. nixos-18.09 for the latest release and nixos-unstable for the latest successful build of master:

% git remote update channels
% git rebase channels/nixos-18.09

For pull requests, please rebase onto nixpkgs master.

NixOS Linux distribution source code is located inside nixos/ folder.

• NixOS installation instructions
• Documentation (Nix Expression Language chapter)
• Manual (How to write packages for Nix)
• Manual (NixOS)
• Community maintained wiki
• Continuous package builds for unstable/master
• Continuous package builds for 18.09 release
• Tests for unstable/master
• Tests for 18.09 release

Communication:

• Discourse Forum
• IRC - #nixos on freenode.net

Note: MIT license does not apply to the packages built by Nixpkgs, merely to the package descriptions (Nix expressions, build scripts, and so on). It also might not apply to patches included in Nixpkgs, which may be derivative works of the packages to which they apply. The aforementioned artifacts are all covered by the licenses of the respective packages.