/usr/share/man/man3/sd_seat_can_graphical.3.gz is in libsystemd-dev 237-3ubuntu10.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man3/sd_seat_get_active.3.gz
/usr/share/man/man3/sd_seat_get_active.3.gz