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

Results forspf2.ustsg.com

Resolver

Location

TXT

Name	TTL	Value
spf2.ustsg.com	300	v=spf1 ip4:185.217.59.0/24 ip4:162.244.87.54/32 ip4:139.28.145.128/26 ip4:136.143.188.0/24 ip4:135.84.80.0/24 ip4:135.84.82.0/24 ip4:117.20.43.11/32 ip4:199.67.64.0/24 ip4:136.143.184.0/24 ip4:135.84.81.0/24 ip4:135.84.83.0/24 ip4:136.143.160.0/24 ~all