/lib/x86_64-linux-gnu/libdns-export.so.100 is in libdns-export100 1:9.9.5.dfsg-9+deb8u15.
This file is owned by root:root, with mode 0o777.
It is a symlink to /lib/x86_64-linux-gnu/libdns-export.so.100.2.2
/lib/x86_64-linux-gnu/libdns-export.so.100.2.2