Examine source code of YouTube Audio Sync Tool

{
  "name": "__MSG_appName__",
  "short_name": "__MSG_appShortName__",
  "version": "0.0.6resigned1",
  "manifest_version": 2,
  "description": "__MSG_appDescription__",
  "icons": {
    "16": "images/icon-16.png",
    "19": "images/icon-19.png",
    "24": "images/icon-24.png",
    "32": "images/icon-32.png",
    "38": "images/icon-38.png",
    "48": "images/icon-48.png",
    "64": "images/icon-64.png",
    "128": "images/icon-128.png"
  },
  "default_locale": "en",
  "background": {
    "scripts": [
      "scripts/background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "tabs",
    "storage",
    "https://www.youtube.com/watch?v=*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/watch?v=*"
      ],
      "js": [
        "lib/jquery-3.1.1.min.js",
        "lib/jquery-ui.min.js",
        "scripts/contentscript.js"
      ],
      "css": [
        "styles/content.css",
        "lib/jquery-ui.min.css"
      ],
      "run_at": "document_end",
      "all_frames": false
    }
  ],
  "web_accessible_resources": [
    "lib/youtube/www-widgetapi-vfl4Pu_oL/www-widgetapi.js",
    "scripts/yt-embeded.js",
    "images/icon-64-transparent.png",
    "images/icon-close-24.png"
  ],
  "browser_action": {
    "default_icon": {
      "16": "images/icon-16.png",
      "19": "images/icon-19.png",
      "24": "images/icon-24.png",
      "32": "images/icon-32.png",
      "38": "images/icon-38.png",
      "48": "images/icon-48.png",
      "64": "images/icon-64.png",
      "128": "images/icon-128.png"
    },
    "default_title": "__MSG_appName__"
  },
  "author": "hirox.lab@gmail.com",
  "homepage_url": "http://hiroxlab.hatenablog.com",
  "browser_specific_settings": {
    "gecko": {
      "id": "{723de83c-d1e2-4e7a-8db8-03d8871cf2b0}"
    }
  }
}