I understand your argumentation against "spf" prefix. But this has nothing
against prefixed values as whole.
Prefix is misused in a DNS discussion.
spf.domain.tld is a sub-domain, not a prefix. and "domain" is not a suffix
of spf, but the parent domain.
Please do not confuse by creating synonyms for perfectly clear, and
established RFC jargon.
parking what is looking to be quite large SPF TXT records in the zone apex
(domain.tld) will increase the probability that queries for "domain.tld
type=any" will exceed 512 bytes. SPF shoots itself in the foot.
Creating an SPF-specific sub-domain under the @sender.domain which would
contain only SPF records solves the above problem, but creates the problem
of which label for the SPF node.
A convention of spf.domain.tld probably causes no name collision for
99.99% of domains that want to add SPF records.
Suggestive, self-documenting, and free of name collisions: spftxt.domain.tld
Len
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