Examine source code of Keep Quiet Utility

{
  "manifest_version": 2,
  "name": "Keep Quiet Utility",
  "version": "1.2resigned1",
  "description": "The Keep Quiet Utility provides a safe and less stressful internet experience for individuals who are sensitive to unexpected high volume sounds.",
  "icons": {
    "32": "res/icons/keepquiet-32.png",
    "48": "res/icons/keepquiet-48.png",
    "96": "res/icons/keepquiet-96.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "browser_action": {
    "browser_style": true,
    "default_popup": "res/options.html",
    "default_icon": {
      "32": "res/icons/kq-a-32.png",
      "48": "res/icons/kq-a-48.png",
      "96": "res/icons/kq-a-96.png"
    },
    "default_title": "Change Keep Quiet Utility settings"
  },
  "background": {
    "scripts": [
      "keepquiet.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0446460b-32a6-4898-9f9b-f7920ccaaa8a}"
    }
  }
}