Examine source code of Domain Scout

{
  "manifest_version": 2,
  "name": "Domain Scout",
  "description": "Turn any site into domain ideas. Domain Scout finds available, related & premium names plus age status & owner info in your browser",
  "version": "1.1.0",
  "icons": {
    "255": "icon/255.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "https://sfbff.newfold.com/*",
    "https://rdap.verisign.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Default Popup Title",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b431aa01-007a-4f94-b83a-aa8d54e9fdbf}"
    }
  }
}