3.13.0-61.100) is not available, but a newer one is (3.13.0-166.216). We redirected you there.
/lib/modules/4.4.0-109-lowlatency/build is in linux-headers-4.4.0-109-lowlatency 4.4.0-109.132.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/src/linux-headers-4.4.0-109-lowlatency