Examine source code of YouTube toggle

{
  "manifest_version": 2,
  "name": "YouTube toggle",
  "version": "1.1resigned1",
  "author": "Sylvain Milan",
  "description": "Toggle the video of the leftmost YouTube tab through a button or keyboard shortcut.",
  "homepage_url": "https://github.com/Anovs/youtube-toggle",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "content_scripts/youtube.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/icon-32.png",
    "default_title": "Toggle YouTube"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Alt+Shift+P"
      },
      "description": "Toggle the video of the leftmost YouTube tab"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e2ecbf47-48b5-4504-bf21-11df16df943f}"
    }
  }
}