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

Results forwalhalla.work

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-06-03T19:34:46.209	2019-06-03T18:34:44	2019-09-01T18:34:44	breakthrough.bible	walhalla.work	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-06-03T19:34:45.021	2019-06-03T18:34:44	2019-09-01T18:34:44	breakthrough.bible	walhalla.work	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-05-27T01:31:04.142	2019-05-27T00:31:03	2019-08-25T00:31:03	walhalla.work	walhalla.work	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-05-27T01:31:03.042	2019-05-27T00:31:03	2019-08-25T00:31:03	walhalla.work	walhalla.work	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-05-22T19:22:42.846	2019-05-22T18:22:42	2019-08-20T18:22:42	walhalla.work	walhalla.work	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-05-22T19:22:42.331	2019-05-22T18:22:42	2019-08-20T18:22:42	walhalla.work	walhalla.work	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-04-04T03:28:48.709	2019-04-04T02:28:47	2019-07-03T02:28:47	noumea.work	walhalla.work	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-04-04T03:28:47.559	2019-04-04T02:28:47	2019-07-03T02:28:47	noumea.work	walhalla.work	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3