Based on what is written on the homepage[1] of the project, the most recent version of this packages supports Berkeley DB 4.7, 4.8, 5.1, 5.3, 6.1 and 6.2, which suggests that the COMMENT variable should be updated. [1]: https://www.jcea.es/programacion/pybsddb.htm
A commit references this bug: Author: bofh Date: Tue Apr 24 00:04:11 UTC 2018 New revision: 468151 URL: https://svnweb.freebsd.org/changeset/ports/468151 Log: databases/py-bsddb3: Fix COMMENT PR: 226904 Submitted by: 0mp Changes: head/databases/py-bsddb3/Makefile