/usr/arm-linux-gnueabihf/lib/debug/libstdc++.so.6 is in libstdc++6-4.8-dbg-armhf-cross 4.8.2-16ubuntu4cross0.11.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/arm-linux-gnueabihf/lib/debug/libstdc++.so.6.0.19