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

Results foradmin.dev.prexfy.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2021-12-16T06:54:52.713	2021-12-16T05:54:52	2022-03-16T05:54:51	admin.dev.prexfy.com	admin.dev.prexfy.com	C=US, O=Let's Encrypt, CN=R3
2021-12-16T06:54:52.508	2021-12-16T05:54:52	2022-03-16T05:54:51	admin.dev.prexfy.com	admin.dev.prexfy.com	C=US, O=Let's Encrypt, CN=R3
2021-10-17T07:54:11.036	2021-10-17T06:54:10	2022-01-15T06:54:09	admin.dev.prexfy.com	admin.dev.prexfy.com	C=US, O=Let's Encrypt, CN=R3
2021-10-17T07:54:10.797	2021-10-17T06:54:10	2022-01-15T06:54:09	admin.dev.prexfy.com	admin.dev.prexfy.com	C=US, O=Let's Encrypt, CN=R3
2021-10-17T07:53:19.501	2021-10-17T00:00:00	2022-10-16T23:59:59	admin.dev.prexfy.com	admin.dev.prexfy.com	C=US, O="Cloudflare, Inc.", CN=Cloudflare Inc ECC CA-3
2021-10-17T07:53:18.493	2021-10-17T00:00:00	2022-10-16T23:59:59	admin.dev.prexfy.com	admin.dev.prexfy.com	C=US, O="Cloudflare, Inc.", CN=Cloudflare Inc RSA CA-2