Examine source code of Simple Hangouts

{
  "author": "Jakub Koziol",
  "content_scripts": [
    {
      "css": [
        "style.css"
      ],
      "matches": [
        "https://hangouts.google.com/*"
      ]
    }
  ],
  "description": "Hide the background and unnecessary clutter from the hangouts.google.com.",
  "manifest_version": 2,
  "name": "Simple Hangouts",
  "version": "0.6resigned1",
  "browser_specific_settings": {
    "gecko": {
      "id": "{70584017-f23a-4d6b-901e-3de5c8daab90}"
    }
  }
}