Specify unique extension identifier

package.json

@@ -3,6 +3,7 @@
   "name": "tor-browser-settings",
   "version": "1.0.0",
   "description": "Customize Orfox-related settings.",
+  "id": "tor-browser-settings@torproject.org",
   "main": "src/main.js",
   "author": "Thomas Rientjes",
   "permissions": {