Examine source code of Litecoin Hoje

{
  "manifest_version": 2,
  "name": "Litecoin Hoje",
  "description": "Veja a cotação do Litecoin através do DolarHoje.com/litecoin",
  "version": "0.0.6",
  "browser_action": {
    "default_icon": "litecoin.png",
    "default_title": "Litecoin Hoje"
  },
  "background": {
    "scripts": [
      "app.js"
    ],
    "persistent": false
  },
  "icons": {
    "128": "litecoin.png"
  },
  "permissions": [
    "https://dolarhoje.com/"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://dolarhoje.com/litecoin/"
      ],
      "js": [
        "has_extension.js"
      ]
    }
  ],
  "applications": {
    "gecko": {
      "id": "litecoin@dolarhoje.com"
    }
  }
}