/usr/include/gnuradio/qtgui/ is in gnuradio-dev 3.7.9.1-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/gnuradio/qtgui/CMakeLists.txt
/usr/include/gnuradio/qtgui/ConstellationDisplayPlot.h
/usr/include/gnuradio/qtgui/DisplayPlot.h
/usr/include/gnuradio/qtgui/FrequencyDisplayPlot.h
/usr/include/gnuradio/qtgui/HistogramDisplayPlot.h
/usr/include/gnuradio/qtgui/TimeDomainDisplayPlot.h
/usr/include/gnuradio/qtgui/TimeRasterDisplayPlot.h
/usr/include/gnuradio/qtgui/VectorDisplayPlot.h
/usr/include/gnuradio/qtgui/WaterfallDisplayPlot.h
/usr/include/gnuradio/qtgui/api.h
/usr/include/gnuradio/qtgui/ber_sink_b.h
/usr/include/gnuradio/qtgui/const_sink_c.h
/usr/include/gnuradio/qtgui/constellationdisplayform.h
/usr/include/gnuradio/qtgui/displayform.h
/usr/include/gnuradio/qtgui/form_menus.h
/usr/include/gnuradio/qtgui/freq_sink_c.h
/usr/include/gnuradio/qtgui/freq_sink_f.h
/usr/include/gnuradio/qtgui/freqcontrolpanel.h
/usr/include/gnuradio/qtgui/freqdisplayform.h
/usr/include/gnuradio/qtgui/histogram_sink_f.h
/usr/include/gnuradio/qtgui/histogramdisplayform.h
/usr/include/gnuradio/qtgui/number_sink.h
/usr/include/gnuradio/qtgui/numberdisplayform.h
/usr/include/gnuradio/qtgui/plot_raster.h
/usr/include/gnuradio/qtgui/plot_waterfall.h
/usr/include/gnuradio/qtgui/qtgui_types.h
/usr/include/gnuradio/qtgui/sink_c.h
/usr/include/gnuradio/qtgui/sink_f.h
/usr/include/gnuradio/qtgui/spectrumUpdateEvents.h
/usr/include/gnuradio/qtgui/timeRasterGlobalData.h
/usr/include/gnuradio/qtgui/time_raster_sink_b.h
/usr/include/gnuradio/qtgui/time_raster_sink_f.h
/usr/include/gnuradio/qtgui/time_sink_c.h
/usr/include/gnuradio/qtgui/time_sink_f.h
/usr/include/gnuradio/qtgui/timecontrolpanel.h
/usr/include/gnuradio/qtgui/timedisplayform.h
/usr/include/gnuradio/qtgui/timerasterdisplayform.h
/usr/include/gnuradio/qtgui/trigger_mode.h
/usr/include/gnuradio/qtgui/utils.h
/usr/include/gnuradio/qtgui/vector_sink_f.h
/usr/include/gnuradio/qtgui/vectordisplayform.h
/usr/include/gnuradio/qtgui/waterfallGlobalData.h
/usr/include/gnuradio/qtgui/waterfall_sink_c.h
/usr/include/gnuradio/qtgui/waterfall_sink_f.h
/usr/include/gnuradio/qtgui/waterfalldisplayform.h