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

Results for*.ubuntu15.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2015-03-29T11:50:32.947	2015-03-27T00:00:00	2015-12-29T23:59:59	sni90412.cloudflaressl.com	*.ubuntu15.com	C=GB, ST=Greater Manchester, L=Salford, O=COMODO CA Limited, CN=COMODO ECC Domain Validation Secure Server CA 2
2015-03-29T11:50:32.947	2015-03-27T00:00:00	2015-12-29T23:59:59	sni90412.cloudflaressl.com	*.ubuntu15.com	C=GB, ST=Greater Manchester, L=Salford, O=COMODO CA Limited, CN=COMODO ECC Domain Validation Secure Server CA 2
2015-03-28T14:24:39.126	2015-03-26T00:00:00	2015-12-29T23:59:59	sni90412.cloudflaressl.com	*.ubuntu15.com	C=GB, ST=Greater Manchester, L=Salford, O=COMODO CA Limited, CN=COMODO ECC Domain Validation Secure Server CA 2
2015-03-28T14:24:39.126	2015-03-26T00:00:00	2015-12-29T23:59:59	sni90412.cloudflaressl.com	*.ubuntu15.com	C=GB, ST=Greater Manchester, L=Salford, O=COMODO CA Limited, CN=COMODO ECC Domain Validation Secure Server CA 2