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

Results formetabase.ai.equitysim.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2018-10-03T18:57:49.162	2018-10-03T17:57:48	2019-01-01T17:57:48	metabase.ai.equitysim.com	metabase.ai.equitysim.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-10-03T18:57:48.358	2018-10-03T17:57:48	2019-01-01T17:57:48	metabase.ai.equitysim.com	metabase.ai.equitysim.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-07-20T20:23:42.524	2018-07-20T19:23:42	2018-10-18T19:23:42	metabase.ai.equitysim.com	metabase.ai.equitysim.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-07-20T20:23:42.314	2018-07-20T19:23:42	2018-10-18T19:23:42	metabase.ai.equitysim.com	metabase.ai.equitysim.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3