Examine source code of Youtube Audio Redirection

{
  "manifest_version": 2,
  "name": "Youtube Audio Redirection",
  "version": "1.0",
  "description": "Redirects audio from YouTube to a user-selectable audio device",
  "permissions": [
    "tabs",
    "webRequest",
    "webRequestBlocking",
    "webNavigation",
    "http://*.youtube.com/*",
    "https://*.youtube.com/*"
  ],
  "browser_action": {
    "default_icon": "icons/icons8-alternative-96.png",
    "default_title": "Youtube Audio Redirection"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{186d7400-0790-4784-b813-0ef59e844736}"
    }
  }
}