/usr/share/man/man1/arm-linux-gnueabihf-gnathtml.1.gz is in gnat-7-arm-linux-gnueabihf 7.3.0-16ubuntu3cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man1/arm-linux-gnueabihf-gnat-7.1.gz