Examine source code of Posture Reminder

{
  "manifest_version": 2,
  "name": "Posture Promoter",
  "version": "1.4.1",
  "description": "Want better posture? Want to maintain a healthier back? This add-on will remind you to sit straight during the day.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "settings.html"
  },
  "permissions": [
    "tabs",
    "storage"
  ]
}