/usr/include/gnuradio/vocoder/ is in gnuradio-dev 3.7.9.1-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/gnuradio/vocoder/alaw_decode_bs.h
/usr/include/gnuradio/vocoder/alaw_encode_sb.h
/usr/include/gnuradio/vocoder/api.h
/usr/include/gnuradio/vocoder/codec2.h
/usr/include/gnuradio/vocoder/codec2_decode_ps.h
/usr/include/gnuradio/vocoder/codec2_encode_sp.h
/usr/include/gnuradio/vocoder/cvsd_decode_bs.h
/usr/include/gnuradio/vocoder/cvsd_encode_sb.h
/usr/include/gnuradio/vocoder/g721_decode_bs.h
/usr/include/gnuradio/vocoder/g721_encode_sb.h
/usr/include/gnuradio/vocoder/g723_24_decode_bs.h
/usr/include/gnuradio/vocoder/g723_24_encode_sb.h
/usr/include/gnuradio/vocoder/g723_40_decode_bs.h
/usr/include/gnuradio/vocoder/g723_40_encode_sb.h
/usr/include/gnuradio/vocoder/gsm_fr_decode_ps.h
/usr/include/gnuradio/vocoder/gsm_fr_encode_sp.h
/usr/include/gnuradio/vocoder/ulaw_decode_bs.h
/usr/include/gnuradio/vocoder/ulaw_encode_sb.h