Man pages matching name systemd-umount in section 1:

systemd-umount.1.de	debian 10 / manpages-de
systemd-umount.1.en	debian 10 / systemd
systemd-umount.1.de	debian 11 / manpages-de
systemd-umount.1.en	debian 11 / systemd
systemd-umount.1.de	debian 12 / manpages-de
systemd-umount.1.en	debian 12 / systemd