/usr/include/libktorrent/torrent/ is in libktorrent-dev 1.3.1-5.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libktorrent/torrent/advancedchokealgorithm.h
/usr/include/libktorrent/torrent/choker.h
/usr/include/libktorrent/torrent/globals.h
/usr/include/libktorrent/torrent/job.h
/usr/include/libktorrent/torrent/jobqueue.h
/usr/include/libktorrent/torrent/peersourcemanager.h
/usr/include/libktorrent/torrent/server.h
/usr/include/libktorrent/torrent/statsfile.h
/usr/include/libktorrent/torrent/timeestimator.h
/usr/include/libktorrent/torrent/torrent.h
/usr/include/libktorrent/torrent/torrentcontrol.h
/usr/include/libktorrent/torrent/torrentcreator.h
/usr/include/libktorrent/torrent/torrentfile.h
/usr/include/libktorrent/torrent/torrentfilestream.h
/usr/include/libktorrent/torrent/torrentstats.h
/usr/include/libktorrent/torrent/uploader.h