It can be anything! An apex, subdomain, or even a URL.
Domain Name: doc.zero.aiDomain Status: No Object Found>>> Last update of WHOIS database: 2024-09-21T16:54:25.273Z <<<
Domain Name: doc.zero.ai
Domain Status: No Object Found
>>> Last update of WHOIS database: 2024-09-21T16:54:25.273Z <<<