/usr/src/linux-headers-3.13.0-68-lowlatency/arch/mn10300 is in linux-headers-3.13.0-68-lowlatency 3.13.0-68.111.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/src/linux-headers-3.13.0-68-lowlatency/arch/../../linux-headers-3.13.0-68/arch/mn10300