Man pages matching name systemd.index in section 7:

systemd.index.7.de	debian 10 / manpages-de
systemd.index.7.en	debian 10 / systemd
systemd.index.7.de	debian 11 / manpages-de
systemd.index.7.en	debian 11 / systemd
systemd.index.7.de	debian 12 / manpages-de
systemd.index.7.en	debian 12 / systemd