/usr/share/man/man3/zzip_realfd.3.gz is in libzzip-dev 0.13.62-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man3/zzip_file_real.3.gz
/usr/share/man/man3/zzip_file_real.3.gz