/usr/share/man/man1/arm-linux-gnueabihf-gnatlink-8.1.gz is in gnat-8-arm-linux-gnueabihf 8-20180414-1ubuntu2cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man1/arm-linux-gnueabihf-gnat-8.1.gz