You've heard about the continually ongoing source code audit in the OpenBSD project. One consequence of the audit is that unused, outdated or downright dangerous stuff gets removed.
Case in point: who here has used spray(8) lately?
Too late now, in OpenBSD 5.6, it's gone, along with rpc.sprayd
We've seen entire subsystems go away entirely or be replaced by modern code (compat libs for old unixen removed, ipf replaced, deprecated APIs and so forth).
OpenBSD 5.6 retires kerberos and tcpwrappers from base along with lpd(1) features requiring hosts.equiv, rcp and a few other items.
Stale, unmaintained code will be removed (such as /proc, likely to go soon). We'll get back to others later.