/usr/lib/libisccfg.so.90 is in libisccfg90 1:9.9.5.dfsg-3ubuntu0.19.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libisccfg.so.90.1.0
/usr/lib/libisccfg.so.90.1.0