/usr/lib/libitkNetlibSlatec-4.10.so is in libinsighttoolkit4-dev 4.10.1-dfsg1-1.1+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libitkNetlibSlatec-4.10.so.1
/usr/lib/libitkNetlibSlatec-4.10.so.1