first try

modules/kde/default.nix

@@ -0,0 +1,12 @@
+{pkgs, ...}:
+{
+  # Should be determined by machine config
+  # services.xserver.enable = true;
+  services.displayManager.sddm.enable = true;
+  services.desktopManager.plasma6.enable = true;
+
+  environment.systemPackages = with pkgs; [
+    firefox # Odd spot, but my choice of browser is determined by environment.
+    kdePackages.kate
+  ];
+}