/usr/include/osl/move_generator/ is in libosl-dev 0.6.0-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/osl/move_generator/addEffect8.h
/usr/include/osl/move_generator/addEffect8.tcc
/usr/include/osl/move_generator/addEffect8Table.h
/usr/include/osl/move_generator/addEffectTable.h
/usr/include/osl/move_generator/addEffectWithEffect.h
/usr/include/osl/move_generator/addEffectWithEffect.tcc
/usr/include/osl/move_generator/addEffect_.h
/usr/include/osl/move_generator/addEffect_.tcc
/usr/include/osl/move_generator/additionalLance.h
/usr/include/osl/move_generator/allMoves.h
/usr/include/osl/move_generator/allMoves.tcc
/usr/include/osl/move_generator/attackToPinned.h
/usr/include/osl/move_generator/attackToPinned.tcc
/usr/include/osl/move_generator/capture_.h
/usr/include/osl/move_generator/capture_.tcc
/usr/include/osl/move_generator/drop.h
/usr/include/osl/move_generator/drop.tcc
/usr/include/osl/move_generator/dropAroundKing8.h
/usr/include/osl/move_generator/escape_.h
/usr/include/osl/move_generator/escape_.tcc
/usr/include/osl/move_generator/kingWalk.h
/usr/include/osl/move_generator/legalMoves.h
/usr/include/osl/move_generator/open.h
/usr/include/osl/move_generator/open.tcc
/usr/include/osl/move_generator/openKingRoad.h
/usr/include/osl/move_generator/pieceOnBoard.h
/usr/include/osl/move_generator/pieceOnBoard.tcc
/usr/include/osl/move_generator/promoteType.h
/usr/include/osl/move_generator/promote_.h
/usr/include/osl/move_generator/promote_.tcc
/usr/include/osl/move_generator/readme.h
/usr/include/osl/move_generator/safeDropMajorPiece.h