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

Results forwebmail.fightstat.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2017-09-22T18:44:47.247	2017-09-20T00:00:00	2017-12-19T23:59:59	fightstat.com	webmail.fightstat.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-07-08T18:49:03.884	2017-07-06T00:00:00	2017-10-04T23:59:59	fightstat.com	webmail.fightstat.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2017-04-24T22:13:41.454	2017-04-21T00:00:00	2017-07-20T23:59:59	fightstat.com	webmail.fightstat.com	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"