Man pages matching name idmapd in section 8:

idmapd.8.en	debian 10 / nfs-common
idmapd.8.fr	debian 11 / manpages-fr
idmapd.8.en	debian 11 / nfs-common
idmapd.8.fr	debian 12 / manpages-fr
idmapd.8.en	debian 12 / nfs-common