This module allows you to get the public suffix of a domain name using
the Public Suffix List from http://publicsuffix.org

A public suffix is one under which Internet users can directly register names.
Some examples of public suffixes are .com, .co.uk and pvt.k12.wy.us.
Accurately knowing the public suffix of a domain is useful when handling web
browser cookies, highlighting the most important part of a domain name in a
user interface or sorting URLs by web site