/usr/lib/x86_64-linux-gnu/libXfont.so is in libxfont-dev 1:1.5.1-1+deb8u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libXfont.so.1.4.1
/usr/lib/x86_64-linux-gnu/libXfont.so.1.4.1