/usr/lib/x86_64-linux-gnu/libgcab-1.0.so.0 is in libgcab-1.0-0 0.7-2+deb9u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgcab-1.0.so.0.0.0
/usr/lib/x86_64-linux-gnu/libgcab-1.0.so.0.0.0