/usr/include/gnuradio/ is in gr-iio 0.2.36-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/gnuradio/iio/
/usr/include/gnuradio/iio/api.h
/usr/include/gnuradio/iio/converter_ss.h
/usr/include/gnuradio/iio/device_sink.h
/usr/include/gnuradio/iio/device_source.h
/usr/include/gnuradio/iio/fmcomms2_sink.h
/usr/include/gnuradio/iio/fmcomms2_source.h
/usr/include/gnuradio/iio/fmcomms5_sink.h
/usr/include/gnuradio/iio/fmcomms5_source.h
/usr/include/gnuradio/iio/math.h
/usr/include/gnuradio/iio/modulo_const_ff.h
/usr/include/gnuradio/iio/modulo_ff.h
/usr/include/gnuradio/iio/pluto_sink.h
/usr/include/gnuradio/iio/pluto_source.h
/usr/include/gnuradio/iio/power_ff.h