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

Results forwebmail.quicklink.info

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2023-01-13T13:45:41.798	2023-01-13T12:45:41	2023-04-13T12:45:40	*.quicklink.info	*.quicklink.info	C=US, O=Google Trust Services LLC, CN=GTS CA 1P5
2022-11-14T11:19:39.296	2022-11-14T10:19:38	2023-02-12T10:19:37	*.quicklink.info	*.quicklink.info	C=US, O=Google Trust Services LLC, CN=GTS CA 1P5
2022-11-14T08:54:48.955	2022-11-14T07:54:48	2023-02-12T07:54:47	*.quicklink.info	*.quicklink.info	C=US, O=Let's Encrypt, CN=E1
2022-11-14T08:54:48.343	2022-11-14T07:54:48	2023-02-12T07:54:47	*.quicklink.info	*.quicklink.info	C=US, O=Let's Encrypt, CN=E1
2021-07-12T21:02:18.107	2021-07-12T00:00:00	2021-10-10T23:59:59	quicklink.info	webmail.quicklink.info	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"
2021-07-12T21:02:17.521	2021-07-12T00:00:00	2021-10-10T23:59:59	quicklink.info	webmail.quicklink.info	C=US, ST=TX, L=Houston, O="cPanel, Inc.", CN="cPanel, Inc. Certification Authority"