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

Results for*.marktbox.de

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-11-24T21:18:49.676	2019-11-23T00:00:00	2020-11-23T12:00:00	marktbox.de	*.marktbox.de	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2019-11-24T21:18:49.676	2019-11-23T00:00:00	2020-11-23T12:00:00	marktbox.de	*.marktbox.de	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2019-11-23T02:27:52.836	2019-11-23T00:00:00	2020-11-23T12:00:00	marktbox.de	*.marktbox.de	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2019-11-23T02:27:52.836	2019-11-23T00:00:00	2020-11-23T12:00:00	marktbox.de	*.marktbox.de	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1