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

Results fornet.w.cdngslb.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2021-04-16T16:03:05.032	2021-04-16T15:03:04	2021-07-15T15:03:04	api.gszcwz.net.w.cdngslb.com	api.gszcwz.net.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3
2021-04-16T16:03:04.821	2021-04-16T15:03:04	2021-07-15T15:03:04	api.gszcwz.net.w.cdngslb.com	api.gszcwz.net.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3
2021-03-18T05:37:13.723	2021-03-18T04:37:13	2021-06-16T04:37:13	note.dooyu.net.w.cdngslb.com	note.dooyu.net.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3
2021-03-18T05:37:13.468	2021-03-18T04:37:13	2021-06-16T04:37:13	note.dooyu.net.w.cdngslb.com	note.dooyu.net.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3
2020-12-31T14:37:45.632	2020-12-31T13:37:45	2021-03-31T13:37:45	note.dooyu.net.w.cdngslb.com	note.dooyu.net.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3
2020-12-31T14:37:45.376	2020-12-31T13:37:45	2021-03-31T13:37:45	note.dooyu.net.w.cdngslb.com	note.dooyu.net.w.cdngslb.com	C=US, O=Let's Encrypt, CN=R3