/usr/powerpc-linux-gnu/lib/debug/libstdc++.so.6 is in libstdc++6-4.8-dbg-powerpc-cross 4.8.5-4ubuntu2cross3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/powerpc-linux-gnu/lib/debug/libstdc++.so.6.0.19