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

Results forweb.timbr.app

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-05-12T23:44:44.786	2019-05-12T22:44:44	2019-08-10T22:44:44	www.xn--intalacije-19b.si	web.timbr.app	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-05-12T23:44:44.325	2019-05-12T22:44:44	2019-08-10T22:44:44	www.xn--intalacije-19b.si	web.timbr.app	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-03-14T06:44:08.543	2019-03-14T05:44:07	2019-06-12T05:44:07	wayfinderstudios.com	web.timbr.app	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-03-14T06:44:07.519	2019-03-14T05:44:07	2019-06-12T05:44:07	wayfinderstudios.com	web.timbr.app	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-03-14T04:50:57.925	2019-03-14T03:50:56	2019-06-12T03:50:56	web.timbr.app	web.timbr.app	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-03-14T04:50:56.905	2019-03-14T03:50:56	2019-06-12T03:50:56	web.timbr.app	web.timbr.app	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3