/usr/include/x86_64-linux-gnu/libavutil/ is in libavutil-dev 7:2.8.6-1ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/x86_64-linux-gnu/libavutil/adler32.h
/usr/include/x86_64-linux-gnu/libavutil/aes.h
/usr/include/x86_64-linux-gnu/libavutil/attributes.h
/usr/include/x86_64-linux-gnu/libavutil/audio_fifo.h
/usr/include/x86_64-linux-gnu/libavutil/audioconvert.h
/usr/include/x86_64-linux-gnu/libavutil/avassert.h
/usr/include/x86_64-linux-gnu/libavutil/avconfig.h
/usr/include/x86_64-linux-gnu/libavutil/avstring.h
/usr/include/x86_64-linux-gnu/libavutil/avutil.h
/usr/include/x86_64-linux-gnu/libavutil/base64.h
/usr/include/x86_64-linux-gnu/libavutil/blowfish.h
/usr/include/x86_64-linux-gnu/libavutil/bprint.h
/usr/include/x86_64-linux-gnu/libavutil/bswap.h
/usr/include/x86_64-linux-gnu/libavutil/buffer.h
/usr/include/x86_64-linux-gnu/libavutil/camellia.h
/usr/include/x86_64-linux-gnu/libavutil/cast5.h
/usr/include/x86_64-linux-gnu/libavutil/channel_layout.h
/usr/include/x86_64-linux-gnu/libavutil/common.h
/usr/include/x86_64-linux-gnu/libavutil/cpu.h
/usr/include/x86_64-linux-gnu/libavutil/crc.h
/usr/include/x86_64-linux-gnu/libavutil/dict.h
/usr/include/x86_64-linux-gnu/libavutil/display.h
/usr/include/x86_64-linux-gnu/libavutil/downmix_info.h
/usr/include/x86_64-linux-gnu/libavutil/error.h
/usr/include/x86_64-linux-gnu/libavutil/eval.h
/usr/include/x86_64-linux-gnu/libavutil/ffversion.h
/usr/include/x86_64-linux-gnu/libavutil/fifo.h
/usr/include/x86_64-linux-gnu/libavutil/file.h
/usr/include/x86_64-linux-gnu/libavutil/frame.h
/usr/include/x86_64-linux-gnu/libavutil/hash.h
/usr/include/x86_64-linux-gnu/libavutil/hmac.h
/usr/include/x86_64-linux-gnu/libavutil/imgutils.h
/usr/include/x86_64-linux-gnu/libavutil/intfloat.h
/usr/include/x86_64-linux-gnu/libavutil/intreadwrite.h
/usr/include/x86_64-linux-gnu/libavutil/lfg.h
/usr/include/x86_64-linux-gnu/libavutil/log.h
/usr/include/x86_64-linux-gnu/libavutil/lzo.h
/usr/include/x86_64-linux-gnu/libavutil/macros.h
/usr/include/x86_64-linux-gnu/libavutil/mathematics.h
/usr/include/x86_64-linux-gnu/libavutil/md5.h
/usr/include/x86_64-linux-gnu/libavutil/mem.h
/usr/include/x86_64-linux-gnu/libavutil/motion_vector.h
/usr/include/x86_64-linux-gnu/libavutil/murmur3.h
/usr/include/x86_64-linux-gnu/libavutil/old_pix_fmts.h
/usr/include/x86_64-linux-gnu/libavutil/opt.h
/usr/include/x86_64-linux-gnu/libavutil/parseutils.h
/usr/include/x86_64-linux-gnu/libavutil/pixdesc.h
/usr/include/x86_64-linux-gnu/libavutil/pixelutils.h
/usr/include/x86_64-linux-gnu/libavutil/pixfmt.h
/usr/include/x86_64-linux-gnu/libavutil/random_seed.h
/usr/include/x86_64-linux-gnu/libavutil/rational.h
/usr/include/x86_64-linux-gnu/libavutil/replaygain.h
/usr/include/x86_64-linux-gnu/libavutil/ripemd.h
/usr/include/x86_64-linux-gnu/libavutil/samplefmt.h
/usr/include/x86_64-linux-gnu/libavutil/sha.h
/usr/include/x86_64-linux-gnu/libavutil/sha512.h
/usr/include/x86_64-linux-gnu/libavutil/stereo3d.h
/usr/include/x86_64-linux-gnu/libavutil/tea.h
/usr/include/x86_64-linux-gnu/libavutil/threadmessage.h
/usr/include/x86_64-linux-gnu/libavutil/time.h
/usr/include/x86_64-linux-gnu/libavutil/timecode.h
/usr/include/x86_64-linux-gnu/libavutil/timestamp.h
/usr/include/x86_64-linux-gnu/libavutil/twofish.h
/usr/include/x86_64-linux-gnu/libavutil/version.h
/usr/include/x86_64-linux-gnu/libavutil/xtea.h