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

Results for*.env.test.ssl.applers.de

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2020-03-06T08:16:47.604	2020-03-06T07:16:47	2020-06-04T07:16:47	*.env.test.ssl.applers.de	*.env.test.ssl.applers.de	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-03-06T08:16:47.604	2020-03-06T07:16:47	2020-06-04T07:16:47	*.env.test.ssl.applers.de	*.env.test.ssl.applers.de	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-03-06T08:16:47.418	2020-03-06T07:16:47	2020-06-04T07:16:47	*.env.test.ssl.applers.de	*.env.test.ssl.applers.de	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2020-03-06T08:16:47.418	2020-03-06T07:16:47	2020-06-04T07:16:47	*.env.test.ssl.applers.de	*.env.test.ssl.applers.de	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3