Examine source code of Ouro Hoje

{
  "manifest_version": 2,
  "name": "Ouro Hoje",
  "description": "Veja a cotação da grama do ouro através do DolarHoje.com/ouro",
  "version": "0.40resigned1",
  "browser_action": {
    "default_icon": "ouro.png",
    "default_title": "Ouro Hoje"
  },
  "background": {
    "scripts": [
      "app.js"
    ],
    "persistent": false
  },
  "icons": {
    "128": "ouro.png"
  },
  "content_security_policy": "script-src 'self' https://ssl.google-analytics.com; object-src 'self'",
  "permissions": [
    "http://ourohoje.com/",
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": [
        "http://dolarhoje.com/ouro/"
      ],
      "js": [
        "has_extension.js"
      ]
    }
  ],
  "applications": {
    "gecko": {
      "id": "ouro@dolarhoje.com"
    }
  }
}