/usr/lib/x86_64-linux-gnu/hdf5/serial/libhdf5_hl.so is in libhdf5-dev 1.8.13+docs-15+deb8u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/hdf5/serial/../../libhdf5_serial_hl.so