Adds comments.

citrus.nix

@@ -2,20 +2,27 @@
 {
   system.stateVersion = "23.05";
 
+  # Enables flakes and the updated `nix` command
   nix.settings.experimental-features = [ "nix-command" "flakes" ];
 
+  # Enables opengl support
   hardware.opengl.enable = true;
 
+  # Includes packages needed for startx
   environment.systemPackages = with pkgs; [
     xorg.xauth xorg.xinit
   ];
   
   users = {
+    # No need to edit users on a single-purpose system.
     mutableUsers = false;
     users = {
+      # My authorized keys are used for remote access
+      #  CHANGE THIS if forking
       root.openssh.authorizedKeys.keyFiles = [
         ./authorized_keys
       ];
+      # Unprivledged user for running the application.
       appuser = {
         isNormalUser = true;
         group = "appuser";
@@ -27,6 +34,7 @@
     };
   };
 
+  # Allow SSH with authorized keys only!
   services.openssh = {
     enable = true;
     settings.PasswordAuthentication = false;

flake.nix

@@ -13,6 +13,7 @@
   outputs = inputs@{self, nixpkgs, flake-utils, ...}:
   flake-utils.lib.eachDefaultSystem (system:
     let
+    # nixpkgs for native system.
     pkgs = import nixpkgs {
       inherit system;
       overlays = [
@@ -20,6 +21,7 @@
         inputs.colmena.overlay
       ];
     };
+    # Native VM config.
     clementine = nixpkgs.lib.nixosSystem {
       inherit pkgs;
       modules = [
@@ -28,27 +30,33 @@
       ];
     };
     in rec {
+      # Install colmena in dev shell for deployment.
       devShell = pkgs.mkShell {
         packages = with pkgs; [ colmena ];
       };
+      # Run testing VM using `nix run`
       packages.default = clementine.config.system.build.vm;
     }) // (let
+      # Target device (RPi3 aarch64) nixpkgs.
       pkgs = import nixpkgs {
         system = "aarch64-linux";
         overlays = [ inputs.graphfix.overlay ];
       };
+      # Modules for colmena and sd card image are the same.
       modules = [
         ./citrus.nix
         "${nixpkgs}/nixos/modules/installer/sd-card/sd-image-aarch64.nix"
         ./platforms/orange.nix
       ];
     in {
+      # Colmena deploy manifest
       colmena = {
         meta.nixpkgs = pkgs;
         orange = {
           imports = modules;
         };
       };
+      # SD card image build.
       orange = (nixpkgs.lib.nixosSystem {
           inherit pkgs modules;
         }).config.system.build.sdImage;