/usr/share/help/C/ is in gnome-boxes 3.18.1-1.1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/help/C/gnome-boxes/
/usr/share/help/C/gnome-boxes/clipboard.page
/usr/share/help/C/gnome-boxes/connect.page
/usr/share/help/C/gnome-boxes/continuous.page
/usr/share/help/C/gnome-boxes/create.page
/usr/share/help/C/gnome-boxes/delete.page
/usr/share/help/C/gnome-boxes/disk-images.page
/usr/share/help/C/gnome-boxes/figures/
/usr/share/help/C/gnome-boxes/figures/boxes_icon.png
/usr/share/help/C/gnome-boxes/index.page
/usr/share/help/C/gnome-boxes/interface.page
/usr/share/help/C/gnome-boxes/legal.xml
/usr/share/help/C/gnome-boxes/prop-system.page
/usr/share/help/C/gnome-boxes/prop-trouble.page
/usr/share/help/C/gnome-boxes/search.page
/usr/share/help/C/gnome-boxes/shortcuts.page
/usr/share/help/C/gnome-boxes/shutdown.page
/usr/share/help/C/gnome-boxes/snapshot-create.page
/usr/share/help/C/gnome-boxes/snapshot-delete.page
/usr/share/help/C/gnome-boxes/snapshot-rename.page
/usr/share/help/C/gnome-boxes/snapshot-revert.page
/usr/share/help/C/gnome-boxes/supported-protocols.page
/usr/share/help/C/gnome-boxes/system-requirements.page
/usr/share/help/C/gnome-boxes/usb-redirection.page
/usr/share/help/C/gnome-boxes/virtualization.page
/usr/share/help/C/gnome-boxes/what-is-a-virtual-machine.page
/usr/share/help/C/gnome-boxes/why-do-i-need-virtual-machine.page