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

Results forinternal-test.donefirst.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2022-02-25T16:57:25.279	2022-02-25T15:57:24	2022-05-26T15:57:23	internal-test.donefirst.com	internal-test.donefirst.com	C=US, O=Let's Encrypt, CN=R3
2022-02-25T16:57:24.937	2022-02-25T15:57:24	2022-05-26T15:57:23	internal-test.donefirst.com	internal-test.donefirst.com	C=US, O=Let's Encrypt, CN=R3
2021-10-22T07:07:58.546	2021-10-22T06:07:58	2022-01-20T06:07:57	internal-test.donefirst.com	internal-test.donefirst.com	C=US, O=Let's Encrypt, CN=R3
2021-10-22T07:07:58.314	2021-10-22T06:07:58	2022-01-20T06:07:57	internal-test.donefirst.com	internal-test.donefirst.com	C=US, O=Let's Encrypt, CN=R3