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

Results fordev.cluster.migom.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2020-06-03T18:07:01.347	2020-06-03T17:07:01	2020-09-01T17:07:01	api.dev.cluster.migom.com	api.dev.cluster.migom.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-06-03T18:07:01.195	2020-06-03T17:07:01	2020-09-01T17:07:01	api.dev.cluster.migom.com	api.dev.cluster.migom.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-06-03T15:21:31.415	2020-06-03T14:21:31	2020-09-01T14:21:31	migom-web-ui.dev.cluster.migom.com	migom-web-ui.dev.cluster.migom.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-06-03T15:21:31.193	2020-06-03T14:21:31	2020-09-01T14:21:31	migom-web-ui.dev.cluster.migom.com	migom-web-ui.dev.cluster.migom.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3