Get the public suffix (TLD or effective TLD) for a hostname. Uses an embedded Public Suffix List covering ccTLDs, common second-level registrations, wildcards, and exceptions.
Fully qualified hostname (e.g., "www.example.co.uk")
The public suffix (e.g., "co.uk"), or null for empty/invalid input
Get the public suffix (TLD or effective TLD) for a hostname. Uses an embedded Public Suffix List covering ccTLDs, common second-level registrations, wildcards, and exceptions.