Examine source code of Redirect2WppWeb

{
  "manifest_version": 2,
  "name": "Redirect2WppWeb",
  "version": "1.0.1",
  "description": "Detecta números de celular e cria atalhos para o WhatsApp Web.",
  "permissions": [
    "contextMenus",
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "icons": {
    "128": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "options_page": "options.html",
  "browser_action": {
    "default_title": "Redirect2WppWeb",
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{08b51523-9104-4417-8156-6afbb409253d}"
    }
  }
}