Examine source code of URL Expander

{
  "manifest_version": 2,
  "name": "URL Expander",
  "version": "1.0",
  "description": "Automatically shows the full URL when hovering over a shortened URL.",
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "16": "icons/icon.png",
    "48": "icons/icon.png",
    "128": "icons/icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f49abe70-d024-4663-bc44-1ecf86873c8d}"
    }
  }
}