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

Results fortestingapp7.app.codelify.io

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2020-01-05T13:08:18.151	2020-01-05T12:08:17	2020-04-04T12:08:17	*.app.codelify.io	*.app.codelify.io	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-01-05T13:08:18.027	2020-01-05T12:08:17	2020-04-04T12:08:17	*.app.codelify.io	*.app.codelify.io	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-11-23T15:42:32.042	2019-11-23T14:42:31	2020-02-21T14:42:31	testingapp7.app.codelify.io	testingapp7.app.codelify.io	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-11-23T15:42:31.843	2019-11-23T14:42:31	2020-02-21T14:42:31	testingapp7.app.codelify.io	testingapp7.app.codelify.io	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-10-05T01:46:44.92	2019-10-05T00:46:44	2020-01-03T00:46:44	*.codelify.io	*.app.codelify.io	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2019-10-05T01:46:44.296	2019-10-05T00:46:44	2020-01-03T00:46:44	*.codelify.io	*.app.codelify.io	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3