/usr/share/man/man1/heka2itx.1.gz is in biosig-tools 0.96.3+svn2677-2.1build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man1/save2gdf.1.gz
/usr/share/man/man1/save2gdf.1.gz