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

Results forwebdisk.excelmac.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2020-07-15T16:33:59.628	2020-07-13T00:00:00	2021-07-14T12:00:00	excelmac.com	*.excelmac.com	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2020-07-13T19:35:46.833	2020-07-13T00:00:00	2021-07-14T12:00:00	excelmac.com	*.excelmac.com	C=US, O=DigiCert Inc, OU=www.digicert.com, CN=Encryption Everywhere DV TLS CA - G1
2020-03-25T10:48:54.269	2020-03-25T00:00:00	2020-06-23T23:59:59	excelmac.com	webdisk.excelmac.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2020-03-25T10:48:53.587	2020-03-25T00:00:00	2020-06-23T23:59:59	excelmac.com	webdisk.excelmac.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2019-09-05T04:05:00.694	2019-09-05T00:00:00	2019-12-04T23:59:59	excelmac.com	webdisk.excelmac.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2019-09-05T04:04:15.253	2019-09-05T00:00:00	2019-12-04T23:59:59	excelmac.com	webdisk.excelmac.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"