Examine source code of Email Validator Pro

{
  "name": "Email Validator Pro",
  "description": "Validate emails for format, deliverability, free mail providers, and disposable addresses — ensure clean, reliable email data",
  "version": "0.0.1",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "index.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "128": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{61dafa58-a8d5-4663-8473-73c803bdfe92}"
    }
  }
}