Examine source code of Focused Google

{
  "manifest_version": 2,
  "name": "Focused Google",
  "version": "1.0",
  "description": "Removes unnecessary clutter from Google search",
  "icons": {
    "48": "icons/trash-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://google.com/*",
        "*://google.de/*",
        "*://google.co.uk/*",
        "*://www.google.com/*",
        "*://www.google.de/*",
        "*://www.google.co.uk/*"
      ],
      "js": [
        "whitespacer.js"
      ]
    }
  ]
}