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

Results fortracker.bedrn.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-05-14T08:38:58.331	2019-05-14T07:38:57	2019-08-12T07:38:57	bedrn.com	tracker.bedrn.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-05-14T08:38:57.462	2019-05-14T07:38:57	2019-08-12T07:38:57	bedrn.com	tracker.bedrn.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-03-15T00:55:37.479	2019-03-14T23:55:36	2019-06-12T23:55:36	bedrn.com	tracker.bedrn.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-03-15T00:55:36.199	2019-03-14T23:55:36	2019-06-12T23:55:36	bedrn.com	tracker.bedrn.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-01-13T21:40:42.446	2019-01-13T20:40:41	2019-04-13T20:40:41	bedrn.com	tracker.bedrn.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-01-13T21:40:41.494	2019-01-13T20:40:41	2019-04-13T20:40:41	bedrn.com	tracker.bedrn.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-11-14T17:26:07.988	2018-11-14T16:26:07	2019-02-12T16:26:07	bedrn.com	tracker.bedrn.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-11-14T17:26:07.426	2018-11-14T16:26:07	2019-02-12T16:26:07	bedrn.com	tracker.bedrn.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3