Examine source code of WAIncognito

{
  "manifest_version": 3,
  "name": "WAIncognito",
  "short_name": "WAIncognito",
  "description": "Be invisible on WhatsApp™ Web by disabling read receipts and presence updates",
  "version": "2.0.9",
  "browser_specific_settings": {
    "gecko": {
      "id": "waincognito@waincognito.com"
    }
  },
  "permissions": [
    "storage"
  ],
  "icons": {
    "128": "images/icon_128_blue.png"
  },
  "action": {
    "default_icon": "images/icon_128_reshaped.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "host_permissions": [
    "https://web.whatsapp.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://web.whatsapp.com/*"
      ],
      "js": [
        "core_injection.js"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "https://web.whatsapp.com/*"
      ],
      "js": [
        "core/ui_class_names.js",
        "core/ui.js",
        "lib/drop.js",
        "lib/sweetalert.min.js"
      ],
      "css": [
        "styles.css",
        "lib/css/drop-theme-basic.css"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "lib/*",
        "core/*",
        "images/*"
      ],
      "matches": [
        "https://web.whatsapp.com/*"
      ]
    }
  ]
}