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

Results forwww.troye-sivan.madeinkatana.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2018-05-30T14:36:53.341	2018-05-30T13:36:53	2018-08-28T13:36:53	troye-sivan.madeinkatana.com	troye-sivan.madeinkatana.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-05-30T14:36:53.167	2018-05-30T13:36:53	2018-08-28T13:36:53	troye-sivan.madeinkatana.com	troye-sivan.madeinkatana.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-05-25T03:28:02.902	2018-05-25T02:28:02	2018-08-23T02:28:02	troye-sivan.madeinkatana.com	troye-sivan.madeinkatana.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-05-25T03:28:02.687	2018-05-25T02:28:02	2018-08-23T02:28:02	troye-sivan.madeinkatana.com	troye-sivan.madeinkatana.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3