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

Results for*.atac.app

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2019-08-29T00:16:42.111	2019-08-29T00:00:00	2020-08-28T12:00:00	sni.cloudflaressl.com	*.atac.app	C=US, ST=CA, L=San Francisco, O="CloudFlare, Inc.", CN=CloudFlare Inc ECC CA-2
2019-08-29T00:16:42.111	2019-08-29T00:00:00	2020-08-28T12:00:00	sni.cloudflaressl.com	*.atac.app	C=US, ST=CA, L=San Francisco, O="CloudFlare, Inc.", CN=CloudFlare Inc ECC CA-2
2019-08-28T20:53:19.079	2019-08-28T00:00:00	2020-08-27T12:00:00	sni.cloudflaressl.com	*.atac.app	C=US, ST=CA, L=San Francisco, O="CloudFlare, Inc.", CN=CloudFlare Inc ECC CA-2
2019-08-28T20:53:19.079	2019-08-28T00:00:00	2020-08-27T12:00:00	sni.cloudflaressl.com	*.atac.app	C=US, ST=CA, L=San Francisco, O="CloudFlare, Inc.", CN=CloudFlare Inc ECC CA-2