/usr/lib/x86_64-linux-gnu/libkadm5srv.so is in libkrb5-dev 1.15-1+deb9u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/mit-krb5/libkadm5srv.so
/usr/lib/x86_64-linux-gnu/mit-krb5/libkadm5srv.so