/usr/include/clutter-gst-3.0/clutter-gst/ is in libclutter-gst-3.0-dev 3.0.26-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-aspectratio.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-camera-device.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-camera-manager.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-camera.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-content.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-crop.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-enum-types.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-playback.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-player.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-types.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-util.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-version.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst-video-sink.h
/usr/include/clutter-gst-3.0/clutter-gst/clutter-gst.h