Examine source code of Domain Info

{
  "name": "Domain info",
  "description": "Shows really detailed info about a domain, like registration status & dates, WHOIS, Name Servers and DNS records",
  "version": "1.4.1",
  "manifest_version": 2,
  "icons": {
    "48": "icons/icon_48.png",
    "128": "icons/icon_128.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_title": "domain-info",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options/options.html",
    "chrome_style": true
  }
}