Examine source code of RadioCast

{
  "manifest_version": 2,
  "name": "RadioCast",
  "description": "Extensión para el radio cast",
  "version": "0.4.1",
  "default_locale": "es",
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "RadioCast"
  },
  "icons": {
    "16": "/icons/icon16.png",
    "48": "/icons/icon48.png",
    "128": "/icons/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.twitch.tv/*",
        "*://twitch.tv/*"
      ],
      "js": [
        "inject.js"
      ]
    }
  ],
  "permissions": [
    "https://www.twitch.tv/*",
    "https://twitch.tv/*"
  ]
}