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

Results for*.test.aarnuk.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2021-04-19T13:12:02.737	2021-04-19T12:12:02	2021-07-18T12:12:02	*.test.aarnuk.com	*.test.aarnuk.com	C=US, O=Let's Encrypt, CN=R3
2021-04-19T13:12:02.737	2021-04-19T12:12:02	2021-07-18T12:12:02	*.test.aarnuk.com	*.test.aarnuk.com	C=US, O=Let's Encrypt, CN=R3
2021-04-19T13:12:02.401	2021-04-19T12:12:02	2021-07-18T12:12:02	*.test.aarnuk.com	*.test.aarnuk.com	C=US, O=Let's Encrypt, CN=R3
2021-04-19T13:12:02.401	2021-04-19T12:12:02	2021-07-18T12:12:02	*.test.aarnuk.com	*.test.aarnuk.com	C=US, O=Let's Encrypt, CN=R3
2021-04-19T12:55:18.824	2021-04-19T11:55:18	2021-07-18T11:55:18	*.test.aarnuk.com	*.test.aarnuk.com	C=US, O=Let's Encrypt, CN=R3
2021-04-19T12:55:18.824	2021-04-19T11:55:18	2021-07-18T11:55:18	*.test.aarnuk.com	*.test.aarnuk.com	C=US, O=Let's Encrypt, CN=R3
2021-04-19T12:55:18.64	2021-04-19T11:55:18	2021-07-18T11:55:18	*.test.aarnuk.com	*.test.aarnuk.com	C=US, O=Let's Encrypt, CN=R3
2021-04-19T12:55:18.64	2021-04-19T11:55:18	2021-07-18T11:55:18	*.test.aarnuk.com	*.test.aarnuk.com	C=US, O=Let's Encrypt, CN=R3