/usr/lib/libitkvnl_algo.so is in libinsighttoolkit3-dev 3.20.1+git20120521-5+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libitkvnl_algo.so.3.20
/usr/lib/libitkvnl_algo.so.3.20