Though the full license text isn't included, several files (cpdup.1, cpdup.c, fsmid.c, and md5.c) all contain disclaimers such as "Permission to use and distribute based on the (DragonFly|FreeBSD) copyright. Supplied as-is". I think Matt Dillon's intent is clear enough to define LICENSE=BSD in the port.
Created attachment 181166 [details] define LICENSE
Actually, we should probably define LICENSE=BSD3CLAUSE, because that's the license in DragonFly's top-level COPYRIGHT file.
(Maintainer timeout) Actually you can't use LICENSE=BSD since it's ambiguous. It states "FreeBSD license" and FreeBSD currently uses BSD2CLAUSE, but AFAIK that has changed over time, so BSD3CLAUSE may have been intended. I've asked Matthew on IRC, awaiting reply.
A commit references this bug: Author: amdmi3 Date: Mon Apr 10 16:40:23 UTC 2017 New revision: 438187 URL: https://svnweb.freebsd.org/changeset/ports/438187 Log: - Add license PR: 218100 Submitted by: gudfitz@gmail.com Approved by: maintainer timeout (gmarco@gufi.org, 2 weeks) Changes: head/sysutils/cpdup/Makefile