/usr/include/strigi/ is in libstreams-dev 0.7.8-1.2+b2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/strigi/archivereader.h
/usr/include/strigi/arinputstream.h
/usr/include/strigi/bufferedstream.h
/usr/include/strigi/bz2inputstream.h
/usr/include/strigi/cpioinputstream.h
/usr/include/strigi/dataeventinputstream.h
/usr/include/strigi/encodinginputstream.h
/usr/include/strigi/fileinputstream.h
/usr/include/strigi/gzipinputstream.h
/usr/include/strigi/inputstream.h
/usr/include/strigi/inputstreamreader.h
/usr/include/strigi/kmpsearcher.h
/usr/include/strigi/lzmainputstream.h
/usr/include/strigi/mailinputstream.h
/usr/include/strigi/oleinputstream.h
/usr/include/strigi/processinputstream.h
/usr/include/strigi/rpminputstream.h
/usr/include/strigi/sdfinputstream.h
/usr/include/strigi/streambase.h
/usr/include/strigi/streambuffer.h
/usr/include/strigi/strigiconfig.h
/usr/include/strigi/stringstream.h
/usr/include/strigi/stringterminatedsubstream.h
/usr/include/strigi/subinputstream.h
/usr/include/strigi/substreamprovider.h
/usr/include/strigi/substreamproviderprovider.h
/usr/include/strigi/tarinputstream.h
/usr/include/strigi/textutils.h
/usr/include/strigi/zipinputstream.h