/etc/man_db.conf:MANPATH_MAP /usr/games /usr/share/man /usr/games is not used in gentoo since games.eclass: remove last-rited eclass
That's the upstream default in src/man_db.conf.in and in fact the last five MANPATH_MAP entries don't apply to us. Plus, according to manpath(5) the information in man_db.conf isn't even used because /etc/env.d/50baselayout defines an explicit MANPATH. So AFAICS no action is required here.