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

Results for*.jixbook.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2021-09-30T04:10:12.782	2021-08-31T00:00:00	2022-08-31T23:59:59	jixbook.com	*.jixbook.com	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2021-09-30T04:10:12.782	2021-08-31T00:00:00	2022-08-31T23:59:59	jixbook.com	*.jixbook.com	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2021-08-31T13:56:58.127	2021-08-31T00:00:00	2022-08-31T23:59:59	jixbook.com	*.jixbook.com	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2021-08-31T13:56:58.127	2021-08-31T00:00:00	2022-08-31T23:59:59	jixbook.com	*.jixbook.com	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1