Examine source code of Pomodoro.addon

{
  "manifest_version": 2,
  "name": "Pomodoro.addon",
  "version": "3.2",
  "description": "An add on to help you work with pomodoro method",
  "icons": {
    "48": "icons/pomodoro-48.png"
  },
  "permissions": [
    "notifications",
    "storage",
    "activeTab",
    "tabs"
  ],
  "browser_action": {
    "default_icon": "icons/pomodoro-48.png",
    "default_title": "POMODORO.ADDON",
    "default_popup": "view/index_v2.html"
  },
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "alarm.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{027d1e97-971f-4c2c-9304-7ab7f461f12d}"
    }
  }
}