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

Results forhostmaster.hostmaster.vbuck.work

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2022-05-26T06:52:23.082	2022-05-26T05:52:22	2022-08-24T05:52:21	hostmaster.hostmaster.hostmaster.vbuck.work	hostmaster.hostmaster.hostmaster.vbuck.work	C=US, O=Let's Encrypt, CN=R3
2022-05-26T06:52:22.919	2022-05-26T05:52:22	2022-08-24T05:52:21	hostmaster.hostmaster.hostmaster.vbuck.work	hostmaster.hostmaster.hostmaster.vbuck.work	C=US, O=Let's Encrypt, CN=R3
2022-05-09T02:23:20.087	2022-05-09T01:23:19	2022-08-07T01:23:18	hostmaster.hostmaster.vbuck.work	hostmaster.hostmaster.vbuck.work	C=US, O=Let's Encrypt, CN=R3
2022-05-09T02:23:19.866	2022-05-09T01:23:19	2022-08-07T01:23:18	hostmaster.hostmaster.vbuck.work	hostmaster.hostmaster.vbuck.work	C=US, O=Let's Encrypt, CN=R3