{ config, pkgs, ... }:
{
  # Working LAN Internet vs mainline Linux.
  #
  # With the in-tree kernel driver r8169 for the network card (LAN and Wi-Fi), LAN Internet is not working.
  #
  # With the out-of-tree r8168 kernel driver, LAN is working.
  #   https://github.com/avnik/nixos-configs/blob/master/modules/r8168.nix
  #   https://github.com/poscat0x04/nixos-configuration/blob/master/hardware/profiles/r8168.nix
  #   https://github.com/NixOS/nixpkgs/blob/961c422b48b3458a01a9c0f2a24e25a1d61018e9/pkgs/os-specific/linux/r8168/default.nix#L51-L52
  # But this requires an old kernel version (we use 5.15 LTS) as r8168 is broken for 6 <= kernel <= 6.8
  #   https://github.com/NixOS/nixpkgs/issues/256329
  #   -> https://github.com/NixOS/nixpkgs/pull/311238

  boot.blacklistedKernelModules = [ "r8169" ];
  boot.extraModulePackages = [
    config.boot.kernelPackages.r8168
  ];

  # https://nixos.wiki/wiki/Linux_kernel#List_available_kernels
  # List all available kernel versions:
  #   `nix repl` -> `:l <nixpkgs>` -> `pkgs.linuxPackages` and press `TAB`

  # Default value.
  #boot.kernelPackages = pkgs.linuxPackages;
  # Latest stable.
  #boot.kernelPackages = pkgs.linuxPackages_latest;
  # Latest unstable.
  #boot.kernelPackages = pkgs.unstable.linuxPackages_latest;

  # LTS, see https://endoflife.date/linux
  # TODO: When NixOS 26.05 is out, this kernel is near EOL
  #boot.kernelPackages = pkgs.linuxPackages_5_15;

  # LTS, see https://endoflife.date/linux
  # TODO: When NixOS 26.05 is out, this kernel is near EOL
  boot.kernelPackages = pkgs.linuxPackages_6_1;
  nixpkgs.config.allowBroken = true;

  # Hardened.
  # https://archlinux.org/packages/extra/x86_64/linux-hardened/
  # -> https://github.com/anthraxx/linux-hardened
  #boot.kernelPackages = pkgs.linuxPackages_hardened;
  # Free/Libre.
  # https://en.wikipedia.org/wiki/Linux-libre
  #boot.kernelPackages = pkgs.linuxPackages-libre;
}