/lib/x86_64-linux-gnu/libdevmapper-event-lvm2thin.so is in dmeventd 2:1.02.137-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /lib/x86_64-linux-gnu/device-mapper/libdevmapper-event-lvm2thin.so
/lib/x86_64-linux-gnu/device-mapper/libdevmapper-event-lvm2thin.so