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

Results forfreehostnet.org.renderproxy.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2020-02-04T18:20:31.478	2020-02-04T17:20:31	2020-05-04T17:20:31	www.freehostnet.org.renderproxy.com	www.freehostnet.org.renderproxy.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-02-04T18:20:31.341	2020-02-04T17:20:31	2020-05-04T17:20:31	www.freehostnet.org.renderproxy.com	www.freehostnet.org.renderproxy.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-02-04T18:07:54.818	2020-02-04T17:07:54	2020-05-04T17:07:54	freehostnet.org.renderproxy.com	freehostnet.org.renderproxy.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-02-04T18:07:54.541	2020-02-04T17:07:54	2020-05-04T17:07:54	freehostnet.org.renderproxy.com	freehostnet.org.renderproxy.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3