/usr/powerpc-linux-gnu/lib/debug/libstdc++.so is in libstdc++6-6-dbg-powerpc-cross 6.4.0-17ubuntu1cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/powerpc-linux-gnu/lib/debug/libstdc++.so.6.0.22