mue/manifest-opera.json

{
  "manifest_version": 2,
  "name": "Mue",
  "version": "0.1",
  "browser_action": {
   "default_icon": "./assets/img/icon.png"
  },
  "background": {
   "scripts": ["./assets/js/background-opera.js"]
  },
 "permissions": [
   "tabs"
 ]
}