/usr/include/glib-2.0/gobject/ is in libglib2.0-dev 2.56.1-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/glib-2.0/gobject/gbinding.h
/usr/include/glib-2.0/gobject/gboxed.h
/usr/include/glib-2.0/gobject/gclosure.h
/usr/include/glib-2.0/gobject/genums.h
/usr/include/glib-2.0/gobject/glib-types.h
/usr/include/glib-2.0/gobject/gmarshal.h
/usr/include/glib-2.0/gobject/gobject-autocleanups.h
/usr/include/glib-2.0/gobject/gobject.h
/usr/include/glib-2.0/gobject/gobjectnotifyqueue.c
/usr/include/glib-2.0/gobject/gparam.h
/usr/include/glib-2.0/gobject/gparamspecs.h
/usr/include/glib-2.0/gobject/gsignal.h
/usr/include/glib-2.0/gobject/gsourceclosure.h
/usr/include/glib-2.0/gobject/gtype.h
/usr/include/glib-2.0/gobject/gtypemodule.h
/usr/include/glib-2.0/gobject/gtypeplugin.h
/usr/include/glib-2.0/gobject/gvalue.h
/usr/include/glib-2.0/gobject/gvaluearray.h
/usr/include/glib-2.0/gobject/gvaluecollector.h
/usr/include/glib-2.0/gobject/gvaluetypes.h