/usr/share/doc/gdc-multilib-arm-linux-gnueabihf is in gdc-multilib-arm-linux-gnueabihf 4:5.3.1-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/cpp-arm-linux-gnueabihf
/usr/share/doc/cpp-arm-linux-gnueabihf