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

Results forhostmaster.viewtrain.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2023-03-24T13:34:37.497	2023-03-24T12:34:37	2023-06-22T12:34:36	viewtrain.com	*.viewtrain.com	C=US, O=Let's Encrypt, CN=E1
2023-03-24T13:34:37.404	2023-03-24T12:34:37	2023-06-22T12:34:36	viewtrain.com	*.viewtrain.com	C=US, O=Let's Encrypt, CN=E1
2023-03-21T16:31:49.221	2023-03-21T15:31:48	2023-06-19T15:31:47	viewtrain.com	*.viewtrain.com	C=US, O=Let's Encrypt, CN=R3
2023-03-21T16:31:49.056	2023-03-21T15:31:48	2023-06-19T15:31:47	viewtrain.com	*.viewtrain.com	C=US, O=Let's Encrypt, CN=R3
2023-01-17T18:15:02.896	2023-01-17T17:15:02	2023-04-17T17:15:01	viewtrain.com	*.viewtrain.com	C=US, O=Let's Encrypt, CN=R3
2023-01-17T18:15:02.724	2023-01-17T17:15:02	2023-04-17T17:15:01	viewtrain.com	*.viewtrain.com	C=US, O=Let's Encrypt, CN=R3
2022-11-18T16:14:15.872	2022-11-18T15:14:15	2023-02-16T15:14:14	viewtrain.com	*.viewtrain.com	C=US, O=Let's Encrypt, CN=R3
2022-11-18T16:14:15.476	2022-11-18T15:14:15	2023-02-16T15:14:14	viewtrain.com	*.viewtrain.com	C=US, O=Let's Encrypt, CN=R3