/usr/include/ is in libmjpegtools-dev 1:2.1.0+debian-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/mjpegtools/
/usr/include/mjpegtools/mpegtimecode.h
/usr/include/mjpegtools/mpeg2enc/
/usr/include/mjpegtools/mpeg2enc/picture.hh
/usr/include/mjpegtools/mpeg2enc/encodertypes.h
/usr/include/mjpegtools/mpeg2enc/synchrolib.h
/usr/include/mjpegtools/mpeg2enc/mpeg2encparams.h
/usr/include/mjpegtools/mpeg2enc/picturereader.hh
/usr/include/mjpegtools/mpeg2enc/macroblock.hh
/usr/include/mjpegtools/mpeg2enc/quantize.hh
/usr/include/mjpegtools/mpeg2enc/syntaxconsts.h
/usr/include/mjpegtools/mpeg2enc/elemstrmwriter.hh
/usr/include/mjpegtools/mpeg2enc/imageplanes.hh
/usr/include/mjpegtools/mpeg2enc/mpeg2encoder.hh
/usr/include/mjpegtools/mpeg2enc/seqencoder.hh
/usr/include/mjpegtools/mpeg2enc/encoderparams.hh
/usr/include/mjpegtools/mpeg2enc/ontheflyratectlpass2.hh
/usr/include/mjpegtools/mpeg2enc/mpeg2encoptions.hh
/usr/include/mjpegtools/mpeg2enc/mpeg2syntaxcodes.h
/usr/include/mjpegtools/mpeg2enc/streamstate.h
/usr/include/mjpegtools/mpeg2enc/ontheflyratectlpass1.hh
/usr/include/mjpegtools/mpeg2enc/predict_ref.h
/usr/include/mjpegtools/mpeg2enc/ratectl.hh
/usr/include/mjpegtools/mpeg2enc/mpeg2coder.hh
/usr/include/mjpegtools/mpeg2enc/quantize_ref.h
/usr/include/mjpegtools/yuv4mpeg.h
/usr/include/mjpegtools/jpegutils.h
/usr/include/mjpegtools/audiolib.h
/usr/include/mjpegtools/mpegconsts.h
/usr/include/mjpegtools/lav_io.h
/usr/include/mjpegtools/motionsearch.h
/usr/include/mjpegtools/mjpeg_logging.h
/usr/include/mjpegtools/liblavrec.h
/usr/include/mjpegtools/mplex/
/usr/include/mjpegtools/mplex/decodebufmodel.hpp
/usr/include/mjpegtools/mplex/videostrm.hpp
/usr/include/mjpegtools/mplex/multiplexor.hpp
/usr/include/mjpegtools/mplex/aunit.hpp
/usr/include/mjpegtools/mplex/stillsstream.hpp
/usr/include/mjpegtools/mplex/inputstrm.hpp
/usr/include/mjpegtools/mplex/padstrm.hpp
/usr/include/mjpegtools/mplex/bits.hpp
/usr/include/mjpegtools/mplex/systems.hpp
/usr/include/mjpegtools/mplex/outputstrm.hpp
/usr/include/mjpegtools/mplex/aunitbuffer.hpp
/usr/include/mjpegtools/mplex/mplexconsts.hpp
/usr/include/mjpegtools/mplex/interact.hpp
/usr/include/mjpegtools/mplex/audiostrm.hpp
/usr/include/mjpegtools/mplex/stream_params.hpp
/usr/include/mjpegtools/liblavplay.h
/usr/include/mjpegtools/frequencies.h
/usr/include/mjpegtools/avilib.h
/usr/include/mjpegtools/mjpeg_types.h
/usr/include/mjpegtools/format_codes.h
/usr/include/mjpegtools/editlist.h