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

Results forspf.mailinblack.com

Resolver

Location

TXT

Name	TTL	Value
spf.mailinblack.com	300	v=spf1 ip4:20.19.152.74 ip4:91.134.185.208/28 ip4:137.74.84.0/24 ip4:20.74.66.32 ip4:185.209.208.0/22 ip4:78.153.229.169 ip4:13.81.219.34 ip4:52.143.1 91.218 ip4:51.103.26.201 ip4:40.89.132.98 ip4:20.199.104.10 ip4:20.19.188.86 ~all