The configuration of the Nix Packages collection. (For
details, see the Nixpkgs documentation.) It allows you to set
package configuration options.
Global configuration for Nixpkgs.
The complete list of [Nixpkgs configuration options](https://nixos.org/manual/nixpkgs/unstable/#sec-config-options-reference) is in the [Nixpkgs manual section on global configuration](https://nixos.org/manual/nixpkgs/unstable/#chap-packageconfig).