/usr/include/ is in libmatroska-dev 1.4.1-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/matroska/
/usr/include/matroska/KaxSeekHead.h
/usr/include/matroska/KaxTrackEntryData.h
/usr/include/matroska/KaxTags.h
/usr/include/matroska/KaxBlock.h
/usr/include/matroska/KaxDefines.h
/usr/include/matroska/KaxTrackVideo.h
/usr/include/matroska/KaxChapters.h
/usr/include/matroska/KaxContentEncoding.h
/usr/include/matroska/KaxConfig.h
/usr/include/matroska/c/
/usr/include/matroska/c/libmatroska.h
/usr/include/matroska/c/libmatroska_t.h
/usr/include/matroska/KaxInfoData.h
/usr/include/matroska/KaxSegment.h
/usr/include/matroska/KaxVersion.h
/usr/include/matroska/KaxTag.h
/usr/include/matroska/KaxCuesData.h
/usr/include/matroska/KaxAttachments.h
/usr/include/matroska/KaxInfo.h
/usr/include/matroska/KaxTracks.h
/usr/include/matroska/KaxClusterData.h
/usr/include/matroska/KaxTrackAudio.h
/usr/include/matroska/KaxContexts.h
/usr/include/matroska/KaxBlockData.h
/usr/include/matroska/KaxCues.h
/usr/include/matroska/FileKax.h
/usr/include/matroska/KaxCluster.h
/usr/include/matroska/KaxSemantic.h
/usr/include/matroska/KaxAttached.h
/usr/include/matroska/KaxTypes.h