/usr/lib/libFWOSPlugin.so is in libopencascade-ocaf-lite-dev 6.5.0.dfsg-2build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libFWOSPlugin-6.5.0.so
/usr/lib/libFWOSPlugin-6.5.0.so