FreeBSD/pc98 is a port of FreeBSD which aims to run on the NEC PC-98x1 (pc98) architecture. The project's goal is to make FreeBSD/pc98 work the same as FreeBSD on other architectures. Most of the kernel source is already included in the FreeBSD source tree and most of the userland utilities built from the source work fine.
FreeBSD/pc98 is a Tier 2 architecture at the time of 9.0-RELEASE. Although this was a Tier 1 for a long time since 5.0-RELEASE, it was downgraded because of some technical reason.