Here is the relevant section from /etc/man.config
# Useful paths - note that COL should not be defined when
# NROFF is defined as "groff -Tascii" or "groff -Tlatin1";
# not only is it superfluous, but it actually damages the output.
# For use with utf-8, NROFF should be "nroff -mandoc" without -T option.
#
TROFF /usr/bin/groff -Tps -mandoc
NROFF /usr/bin/nroff -c -mandoc
JNROFF /usr/bin/groff -Tnippon -mandocj
EQN /usr/bin/geqn -Tps
NEQN /usr/bin/geqn -Tlatin1
JNEQN /usr/bin/geqn -Tnippon
TBL /usr/bin/gtbl
# COL /usr/bin/col
REFER /usr/bin/grefer
PIC /usr/bin/gpic
VGRIND
GRAP
PAGER /usr/bin/less -isr
CAT /bin/cat
#
# The command "man -a xyzzy" will show all man pages for xyzzy.
# When CMP is defined man will try to avoid showing the same
# text twice. (But compressed pages compare unequal.)
#
CMP /usr/bin/cmp -s
#
# Compress cat pages
#
COMPRESS /bin/gzip
COMPRESS_EXT .gz
#
# Default manual sections (and order) to search if -S is not specified
# and the MANSECT environment variable is not set.
#
MANSECT 1:8:2:3:4:5:6:7:9:tcl:n:l
#
# Default options to use when man is invoked without options
# This is mainly for the benefit of those that think -a should be the default
# Note that some systems have /usr/man/allman, causing pages to be shown twice.
#
#MANDEFOPTIONS -a
#
# Decompress with given decompressor when input file has given extension
# The command given must act as a filter.
#
.gz /bin/gunzip -c
.bz2 /usr/bin/bzip2 -c -d
.z
.Z /bin/zcat
.F
.Y