/usr/include/gphoto2/ is in libgphoto2-dev 2.5.9-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/gphoto2/gphoto2-abilities-list.h
/usr/include/gphoto2/gphoto2-camera.h
/usr/include/gphoto2/gphoto2-context.h
/usr/include/gphoto2/gphoto2-file.h
/usr/include/gphoto2/gphoto2-filesys.h
/usr/include/gphoto2/gphoto2-library.h
/usr/include/gphoto2/gphoto2-list.h
/usr/include/gphoto2/gphoto2-port-info-list.h
/usr/include/gphoto2/gphoto2-port-log.h
/usr/include/gphoto2/gphoto2-port-portability.h
/usr/include/gphoto2/gphoto2-port-result.h
/usr/include/gphoto2/gphoto2-port-version.h
/usr/include/gphoto2/gphoto2-port.h
/usr/include/gphoto2/gphoto2-result.h
/usr/include/gphoto2/gphoto2-setting.h
/usr/include/gphoto2/gphoto2-version.h
/usr/include/gphoto2/gphoto2-widget.h
/usr/include/gphoto2/gphoto2.h