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

Results forwebdisk.revstream.therevapp.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-07-29T04:41:42.468	2019-07-29T00:00:00	2019-10-27T23:59:59	revstream.therevapp.com	webdisk.revstream.therevapp.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2019-07-29T04:41:23.701	2019-07-29T00:00:00	2019-10-27T23:59:59	revstream.therevapp.com	webdisk.revstream.therevapp.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2019-05-14T16:05:32.076	2019-05-14T00:00:00	2019-08-12T23:59:59	revstream.therevapp.com	webdisk.revstream.therevapp.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2019-05-14T16:05:17.543	2019-05-14T00:00:00	2019-08-12T23:59:59	revstream.therevapp.com	webdisk.revstream.therevapp.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"