/usr/share/doc/libobjc-4.8-dev-powerpc-cross is in libobjc-4.8-dev-powerpc-cross 4.8.2-16ubuntu3cross0.11.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gcc-4.8-powerpc-linux-gnu-base
/usr/share/doc/gcc-4.8-powerpc-linux-gnu-base