My guess is this part:

  The iwn(4) driver was added, providing support for the
  Intel® Centrino™ Wireless-N 105 and 135 chipsets. [r266770]

from: https://www.freebsd.org/releases/11.0R/relnotes.html#drivers...

That driver was on OpenBSD for a long time. I put FreeBSD on a machine a year or so ago and really missed that driver. Maybe now I can get rid of the USB dongle I've been using instead.

iwn(4) has been present for a long time. I suspect you mean iwm(4)?

You're right. Also happy to report that machine is working way better now.

I think that should read that these chipsets were added to iwn, considering iwn has been in since at least 8.0 (going by my very non-scientific manpage search).

Typo -- should read additional wireless support has been added.

IIRC, OpenBSD added 802.11n support in a recent release.