Examine source code of New Year Countdown

{
  "manifest_version": 2,
  "name": "New Year Countdown",
  "version": "1.0",
  "description": "Displays a countdown to New Year's Day",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [],
  "browser_action": {
    "default_icon": "icons/icon-48.png",
    "default_title": "New Year Countdown",
    "default_popup": "popup/popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b0c824c5-3c2c-4b77-bb63-7be2b5e7012d}"
    }
  }
}