Examine source code of Fiverr Notification

{
  "author": "sdd",
  "action": {
    "default_icon": {
      "16": "images/icon-16.png",
      "128": "images/icon-128.png"
    }
  },
  "content_scripts": [
    {
      "all_frames": false,
      "js": [
        "scripts/jquery-3.4.1.min.js",
        "scripts/contentscript.js"
      ],
      "matches": [
        "https://www.fiverr.com/*"
      ],
      "run_at": "document_end"
    }
  ],
  "description": "This extension will change the Fiverr Icon whenever a notification is received.",
  "icons": {
    "16": "images/icon-16.png",
    "128": "images/icon-128.png"
  },
  "manifest_version": 3,
  "name": "Fiverr Notification Icon in Title",
  "permissions": [],
  "short_name": "Fiverr Notification Icon in Title",
  "version": "1.3.5",
  "web_accessible_resources": [
    {
      "resources": [
        "images/fiverr-red.png"
      ],
      "matches": [
        "https://www.fiverr.com/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "unique_notificationfivver@example.com",
      "strict_min_version": "109.0"
    }
  }
}