It can be anything! An apex, subdomain, or even a URL.

Results for*.y1998.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2021-08-13T03:36:40.294	2021-08-01T00:00:00	2022-08-01T23:59:59	y1998.com	*.y1998.com	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2021-08-13T03:36:40.294	2021-08-01T00:00:00	2022-08-01T23:59:59	y1998.com	*.y1998.com	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2021-08-01T13:03:17.119	2021-08-01T00:00:00	2022-08-01T23:59:59	y1998.com	*.y1998.com	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2021-08-01T13:03:17.119	2021-08-01T00:00:00	2022-08-01T23:59:59	y1998.com	*.y1998.com	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1