I presume that jggimi reads the
source-changes mailing list, either daily or weekly/monthly bulk digests.
http://www.openbsd.org/mail.html
http://marc.info/?l=openbsd-cvs
Another possibility is that he follows the 'current' FAQ, which is something people should look at occasionally.. always good to prepare for the future.
http://www.openbsd.org/faq/current.html
As you can see, 4.7 will introduce changes to pf that break traditional '
rdr' and '
nat' pseudo-translation-actions entirely.
Man pages are also a good idea, the new match action is documented in
pf.conf(5).
Beware of outdated books, the developers never promised backwards compatibility.. use the
PF FAQ instead.