/usr/lib/syslog-ng/libsyslog-ng.so is in syslog-ng-dev 3.8.1-10.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/syslog-ng/libsyslog-ng-3.8.so.0.0.0
/usr/lib/syslog-ng/libsyslog-ng-3.8.so.0.0.0