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

Results forxyz.w.cdngslb.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2021-07-16T09:15:40.636	2021-07-16T08:15:40	2021-10-14T08:15:38	lkss123.xyz.w.cdngslb.com	lkss123.xyz.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3
2021-07-16T09:15:40.469	2021-07-16T08:15:40	2021-10-14T08:15:38	lkss123.xyz.w.cdngslb.com	lkss123.xyz.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3
2021-07-06T12:39:17.551	2021-07-06T11:39:16	2021-10-04T11:39:15	yanghuayangcao.com	lkss123.xyz.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3
2021-07-06T12:39:16.971	2021-07-06T11:39:16	2021-10-04T11:39:15	yanghuayangcao.com	lkss123.xyz.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3