/usr/include/bullet/BulletCollision/BroadphaseCollision/ is in libbullet-dev 2.81-rev2613+dfsg2-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/bullet/BulletCollision/BroadphaseCollision/btAxisSweep3.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btBroadphaseInterface.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btBroadphaseProxy.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btCollisionAlgorithm.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btDbvt.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btDbvtBroadphase.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btDispatcher.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btMultiSapBroadphase.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btOverlappingPairCache.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btOverlappingPairCallback.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btQuantizedBvh.h
/usr/include/bullet/BulletCollision/BroadphaseCollision/btSimpleBroadphase.h