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

Results forschools.reev.tech

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2020-05-10T01:17:22.518	2020-05-10T00:17:22	2020-08-08T00:17:22	www.verticalgardening.com.au	schools.reev.tech	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-05-10T01:17:22.314	2020-05-10T00:17:22	2020-08-08T00:17:22	www.verticalgardening.com.au	schools.reev.tech	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-03-11T05:23:04.162	2020-03-11T04:23:03	2020-06-09T04:23:03	id.octaos.com	schools.reev.tech	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-03-11T05:23:04.013	2020-03-11T04:23:03	2020-06-09T04:23:03	id.octaos.com	schools.reev.tech	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-01-11T18:08:35.955	2020-01-11T17:08:35	2020-04-10T17:08:35	www.tappyr.com	schools.reev.tech	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-01-11T18:08:35.674	2020-01-11T17:08:35	2020-04-10T17:08:35	www.tappyr.com	schools.reev.tech	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-01-11T11:32:14.693	2020-01-11T10:32:14	2020-04-10T10:32:14	schools.reev.tech	schools.reev.tech	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-01-11T11:32:14.545	2020-01-11T10:32:14	2020-04-10T10:32:14	schools.reev.tech	schools.reev.tech	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3