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

Results for*.test.cdn1.castingnetworks.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-07-22T22:52:03.869	2019-07-22T00:00:00	2020-08-22T12:00:00	*.test.cdn1.castingnetworks.com	*.test.cdn1.castingnetworks.com	C=US, O=Amazon, OU=Server CA 1B, CN=Amazon
2019-07-22T22:52:03.869	2019-07-22T00:00:00	2020-08-22T12:00:00	*.test.cdn1.castingnetworks.com	*.test.cdn1.castingnetworks.com	C=US, O=Amazon, OU=Server CA 1B, CN=Amazon
2018-08-03T17:41:23.862	2018-08-03T00:00:00	2019-09-03T12:00:00	*.test.cdn1.castingnetworks.com	*.test.cdn1.castingnetworks.com	C=US, O=Amazon, OU=Server CA 1B, CN=Amazon
2018-08-03T17:41:23.862	2018-08-03T00:00:00	2019-09-03T12:00:00	*.test.cdn1.castingnetworks.com	*.test.cdn1.castingnetworks.com	C=US, O=Amazon, OU=Server CA 1B, CN=Amazon