/usr/include/osl/game_playing/ is in libosl-dev 0.6.0-3.1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/osl/game_playing/alphaBetaPlayer.h
/usr/include/osl/game_playing/bookPlayer.h
/usr/include/osl/game_playing/computerPlayer.h
/usr/include/osl/game_playing/csaClient.h
/usr/include/osl/game_playing/csaLogger.h
/usr/include/osl/game_playing/csaStopwatch.h
/usr/include/osl/game_playing/csaTime.h
/usr/include/osl/game_playing/cuiClient.h
/usr/include/osl/game_playing/gameManager.h
/usr/include/osl/game_playing/gameState.h
/usr/include/osl/game_playing/gnuShogiClient.h
/usr/include/osl/game_playing/historyToTable.h
/usr/include/osl/game_playing/openingBookTracer.h
/usr/include/osl/game_playing/pvHistory.h
/usr/include/osl/game_playing/readme.h
/usr/include/osl/game_playing/recordTracer.h
/usr/include/osl/game_playing/searchPlayer.h
/usr/include/osl/game_playing/searchPlayer.tcc
/usr/include/osl/game_playing/speculativeAllMoves.h
/usr/include/osl/game_playing/speculativeModel.h
/usr/include/osl/game_playing/speculativeSearchPlayer.h
/usr/include/osl/game_playing/threadForEachMove.h
/usr/include/osl/game_playing/timeKeeper.h
/usr/include/osl/game_playing/usiResponse.h
/usr/include/osl/game_playing/usiState.h
/usr/include/osl/game_playing/weightTracer.h
/usr/include/osl/game_playing/winCountTracer.h