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

Results for2296689g39.secure0102.hubspot.net

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2017-11-30T22:59:41.558	2017-11-30T00:00:00	2018-11-30T12:00:00	2296689g39.secure0102.hubspot.net	2296689g39.secure0102.hubspot.net	C=US, ST=CA, L=San Francisco, O="CloudFlare, Inc.", CN=CloudFlare Inc ECC CA-2
2017-11-30T22:59:39.828	2017-11-30T00:00:00	2018-11-30T12:00:00	2296689g39.secure0102.hubspot.net	2296689g39.secure0102.hubspot.net	C=US, ST=CA, L=San Francisco, O="CloudFlare, Inc.", CN=CloudFlare Inc RSA CA-1
2017-11-30T22:59:38.95	2017-11-30T00:00:00	2018-08-10T12:00:00	2296689g39.secure0102.hubspot.net	2296689g39.secure0102.hubspot.net	C=US, ST=CA, L=San Francisco, O="CloudFlare, Inc.", CN=CloudFlare Inc Compatibility CA-3