Examine source code of UC Booster

{
  "name": "UC Booster",
  "version": "1.0.0",
  "description": "This Extension Promote your your youtube channel and help to engaged right audience",
  "manifest_version": 2,
  "icons": {
    "16": "assets/images/uc_icon16x16.png",
    "32": "assets/images/uc_icon32x32.png",
    "48": "assets/images/uc_icon48x48.png",
    "128": "assets/images/uc_icon128x128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "css": [
        "assets/css/bootstrap.min.css",
        "assets/css/my-style.css"
      ],
      "js": [
        "assets/js/bootstrap.bundle.min.js",
        "assets/js/jquery.min.js",
        "assets/js/cookie.min.js",
        "assets/js/inject-script.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "browser_style": true
  },
  "permissions": [
    "webRequest",
    "<all_urls>",
    "storage",
    "notifications"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{3d8a6a24-dc5c-4bb9-94b4-af93bb927769}"
    }
  }
}