/usr/lib/libflowcanvas.so is in libflowcanvas-dev 0.7.1+dfsg0-0.4build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libflowcanvas.so.5.1.0
/usr/lib/libflowcanvas.so.5.1.0