/usr/bin/aarch64-linux-gnu-gcc-ar is in gcc-aarch64-linux-gnu 4:5.3.1-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/aarch64-linux-gnu-gcc-ar-5
/usr/bin/aarch64-linux-gnu-gcc-ar-5