Examine source code of Whois.com domain-check

{
  "manifest_version": 2,
  "name": "Whois.com domain-check",
  "version": "1.0",
  "description": "Check domain information on whois.com with one click",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Check domain on whois.com"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{233eee3a-04cb-4ad4-8cd0-33f95ffe81c3}"
    }
  }
}