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

Results forspf.gmoserver.jp

Resolver

Location

TXT

Name	TTL	Value
spf.gmoserver.jp	3600	v=spf1 +ip4:157.7.144.0/26 +ip4:157.7.183.0/24 +ip4:210.157.19.64/26 +ip4:157.7.151.0/24 +ip4:210.157.2.48/29 +ip4:210.172.136.64/26 +ip4:157.7.156.168/29 +ip4:160.251.229.0/25 +ip4:163.44.89.0/24 +ip4:150.95.48.0/24 include:_spf.maildeliver.jp ~all