$work has a patch to pw(8) for setting the mode from 0600 for logfiles to 0660 hardcoded in usr.sbin/pw/pw_log.c. There's no reason why this could/shouldn't be controlled in /etc/pw.conf though -- defaulting to 0600.
Hey ngie@, I have created the following review in order to add the new keyword logmode https://reviews.freebsd.org/D24395
(In reply to Sofian Brabez from comment #1) Note that as of 20240120, the DR is still in "needs revision".