--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -6,9 +6,12 @@ module.exports = {
     "mozilla"
   ],
   "rules": {
     "mozilla/import-globals": "warn",
   },
   "env": {
     "es6": true
   },
+  "parserOptions": {
+    "ecmaVersion": 8,
+  },
 };

--- a/toolkit/components/extensions/.eslintrc.js
+++ b/toolkit/components/extensions/.eslintrc.js
@@ -1,17 +1,13 @@
 "use strict";
 
 module.exports = { // eslint-disable-line no-undef
   "extends": "../../.eslintrc.js",
 
-  "parserOptions": {
-    "ecmaVersion": 8,
-  },
-
   "globals": {
     "Cc": true,
     "Ci": true,
     "Components": true,
     "Cr": true,
     "Cu": true,
     "dump": true,
     "TextDecoder": false,