make sure widevine-firefox is only applied to aarch64

home/browsers/firefox/default.nix

@@ -1,9 +1,14 @@
 # https://discourse.nixos.org/t/combining-best-of-system-firefox-and-home-manager-firefox-settings/37721
 # https://discourse.nixos.org/t/declare-firefox-extensions-and-settings/36265
-{ pkgs, config, ... }:
+{
+  pkgs,
+  config,
+  lib,
+  ...
+}:
 
 {
-  home.sessionVariables = rec {
+  home.sessionVariables = lib.mkIf pkgs.stdenv.hostPlatform.isAarch64 {
     MOZ_GMP_PATH = "${pkgs.widevine-firefox}/gmp-widevinecdm/system-installed";
   };
 

packages/widevine-firefox/package.nix

@@ -16,7 +16,6 @@ stdenv.mkDerivation {
   meta = widevine-cdm.meta // {
     platforms = [
       "aarch64-linux"
-      "x86_64-linux"
     ];
   };
 }