/usr/include/libgnomeprint-2.2/libgnomeprint/private/ is in libgnomeprint2.2-dev 2.18.8-3ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gnome-font-private.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gnome-fontmap.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gnome-glyphlist-private.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gnome-print-config-private.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gnome-print-path.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gnome-print-private.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gp-gc-private.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-config.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-key.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-list.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-model.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-node-private.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-node.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-option.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-printer.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-reference.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-root.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-settings.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-state.h
/usr/include/libgnomeprint-2.2/libgnomeprint/private/gpa-utils.h