/usr/share/doc/libhdf5-cpp-100/RELEASE.txt.gz is in libhdf5-cpp-100 1.10.0-patch1+docs-4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libhdf5-cpp-100/changelog.gz
/usr/share/doc/libhdf5-cpp-100/changelog.gz