/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/ is in libbullet-dev 2.87+dfsg-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3BvhInfo.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3ContactCache.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3ConvexHullContact.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3ConvexPolyhedronCL.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3GjkEpa.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3OptimizedBvh.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3QuantizedBvh.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3StridingMeshInterface.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3SupportMappings.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3TriangleCallback.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3TriangleIndexVertexArray.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3VectorFloat4.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/b3VoronoiSimplexSolver.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/kernels/
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/kernels/bvhTraversal.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/kernels/mprKernels.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/kernels/primitiveContacts.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/kernels/satClipHullContacts.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/kernels/satConcaveKernels.h
/usr/include/bullet/Bullet3OpenCL/NarrowphaseCollision/kernels/satKernels.h