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

Results foradmin.ingrid.dev.tmcloud.io

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-03-15T20:41:51.14	2019-03-15T19:41:50	2019-06-13T19:41:50	admin.ingrid.dev.tmcloud.io	admin.ingrid.dev.tmcloud.io	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-03-15T20:41:50.141	2019-03-15T19:41:50	2019-06-13T19:41:50	admin.ingrid.dev.tmcloud.io	admin.ingrid.dev.tmcloud.io	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-12-03T18:46:04.841	2018-12-03T17:46:04	2019-03-03T17:46:04	admin.ingrid.dev.tmcloud.io	admin.ingrid.dev.tmcloud.io	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-12-03T18:46:04.339	2018-12-03T17:46:04	2019-03-03T17:46:04	admin.ingrid.dev.tmcloud.io	admin.ingrid.dev.tmcloud.io	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3