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

Results forwebdisk.starttest.net

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2022-07-02T23:19:49.929	2022-07-02T00:00:00	2022-09-30T23:59:59	starttest.net	webdisk.starttest.net	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2022-07-02T23:19:49.074	2022-07-02T00:00:00	2022-09-30T23:59:59	starttest.net	webdisk.starttest.net	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2022-04-17T13:01:06.485	2022-04-17T00:00:00	2022-07-16T23:59:59	starttest.net	webdisk.starttest.net	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2022-04-17T13:01:00.147	2022-04-17T00:00:00	2022-07-16T23:59:59	starttest.net	webdisk.starttest.net	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"