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

Results for*.plentyous.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2018-06-01T05:05:33.48	2018-06-01T04:05:33	2018-08-30T04:05:33	plentyous.com	*.plentyous.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-06-01T05:05:33.48	2018-06-01T04:05:33	2018-08-30T04:05:33	plentyous.com	*.plentyous.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-06-01T05:05:33.307	2018-06-01T04:05:33	2018-08-30T04:05:33	plentyous.com	*.plentyous.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-06-01T05:05:33.307	2018-06-01T04:05:33	2018-08-30T04:05:33	plentyous.com	*.plentyous.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-03-23T20:06:12.88	2018-03-23T19:06:12	2018-06-21T19:06:12	plentyous.com	*.plentyous.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3
2018-03-23T20:06:12.88	2018-03-23T19:06:12	2018-06-21T19:06:12	plentyous.com	*.plentyous.com	C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3