Examine source code of Play iTunes

{
  "manifest_version": 2,
  "name": "Play iTunes",
  "version": "1.1resigned1",
  "applications": {
    "gecko": {
      "id": "play-itunes@g2p.github.com"
    }
  },
  "permissions": [],
  "content_scripts": [
    {
      "matches": [
        "http://itunes.apple.com/*",
        "https://itunes.apple.com/*"
      ],
      "js": [
        "script.js"
      ]
    }
  ]
}