Examine source code of WhatsApp Shortcuts

{
  "manifest_version": 2,
  "name": "WhatsApp Shortcuts",
  "version": "1.1",
  "description": "Custom shortcuts for WhatsApp Web",
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://web.whatsapp.com/*"
      ],
      "js": [
        "js/content.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options/options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{82c86a5f-2725-466e-a9a4-42fa164e5e3b}"
    }
  }
}