Examine source code of Maximize WhatsApp Web

{
  "manifest_version": 2,
  "name": "Maximize WhatsApp Web",
  "version": "2.3",
  "description": "Enable full viewport for large aspect ratio screens on WhatsApp Web.",
  "icons": {
    "48": "icons/maximize-whatsapp-48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "menezes@pm.me"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://web.whatsapp.com/*"
      ],
      "js": [
        "main.js"
      ]
    }
  ]
}