Examine source code of Soundcloud track

{
  "manifest_version": 2,
  "name": "Soundcloud track",
  "version": "1.0",
  "author": "Aez",
  "description": "Tracks your soundcloud listening time",
  "icons": {
    "48": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://soundcloud.com/*"
      ],
      "js": [
        "app.js"
      ]
    }
  ],
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "browser_style": true,
    "default_popup": "menu.html",
    "default_icon": {
      "48": "icon.png"
    }
  }
}