/usr/lib/x86_64-linux-gnu/libdns_sd.so.1 is in libavahi-compat-libdnssd1 0.6.32~rc+dfsg-1ubuntu2.3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libdns_sd.so.1.0.0
/usr/lib/x86_64-linux-gnu/libdns_sd.so.1.0.0