Examine source code of Mail Validator

{
  "name": "Mail Validator",
  "description": "Mail validator is used to validate email. Functionality  to check deliverability,valid format, free mail,  disposable mail ",
  "version": "0.0.1",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "index.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "128": "icon.png"
  }
}