/usr/lib/scilab/libscisignal_processing.so is in scilab-minimal-bin 5.5.1-7.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/scilab/libscisignal_processing.so.5.5.1
/usr/lib/scilab/libscisignal_processing.so.5.5.1