The first link is for add-on packages which are not part of the OpenBSD
base system.
The second is for patches of the base system.
If I understand your question correctly, you may find the answer here:
http://www.openbsd.org/stable.html
Of interest:
"[..] OpenBSD provides a source tree that contains important patches and
fixes (i.e. those from the errata plus others which are obvious and
simple, but do not deserve an errata entry) [..]"
"[..] * Errata entries are made for bugs which affect many people. Other
patches may be merged into the patch branch if they affect a few people in
drastic ways."
-Martin