Examine source code of FocusTube

{
  "description": "Removes youtube distractions by Limiting you see only the video",
  "manifest_version": 2,
  "name": "FocusTube",
  "version": "2.1resigned1",
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/watch?v*"
      ],
      "js": [
        "page_eater.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icons/FocusTubeLogo.png",
    "default_title": "FocusTube is active"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e0eb1e0e-76fa-4373-b50c-e1b94c5b0d25}"
    }
  }
}