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

Results for*.bart.best

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2020-03-12T09:55:50.891	2020-02-24T00:00:00	2021-02-24T12:00:00	bart.best	*.bart.best	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2020-03-12T09:55:50.891	2020-02-24T00:00:00	2021-02-24T12:00:00	bart.best	*.bart.best	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2020-02-24T15:59:18.615	2020-02-24T00:00:00	2021-02-24T12:00:00	bart.best	*.bart.best	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2020-02-24T15:59:18.615	2020-02-24T00:00:00	2021-02-24T12:00:00	bart.best	*.bart.best	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1