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

Results forportainer.app.dotsdev.org

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2023-01-25T10:44:50.067	2023-01-25T09:44:49	2023-04-25T09:44:48	portainer.app.dotsdev.org	portainer.app.dotsdev.org	C=US, O=Let's Encrypt, CN=R3
2023-01-25T10:44:49.988	2023-01-25T09:44:49	2023-04-25T09:44:48	portainer.app.dotsdev.org	portainer.app.dotsdev.org	C=US, O=Let's Encrypt, CN=R3
2022-10-13T06:18:43.154	2022-10-13T05:18:42	2023-01-11T05:18:41	portainer.app.dotsdev.org	portainer.app.dotsdev.org	C=US, O=Let's Encrypt, CN=R3
2022-10-13T06:18:42.534	2022-10-13T05:18:42	2023-01-11T05:18:41	portainer.app.dotsdev.org	portainer.app.dotsdev.org	C=US, O=Let's Encrypt, CN=R3