/usr/include/bullet/BulletCollision/Gimpact/ is in libbullet-dev 2.82-r2704+dfsg-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/bullet/BulletCollision/Gimpact/btBoxCollision.h
/usr/include/bullet/BulletCollision/Gimpact/btClipPolygon.h
/usr/include/bullet/BulletCollision/Gimpact/btCompoundFromGimpact.h
/usr/include/bullet/BulletCollision/Gimpact/btContactProcessing.h
/usr/include/bullet/BulletCollision/Gimpact/btGImpactBvh.h
/usr/include/bullet/BulletCollision/Gimpact/btGImpactCollisionAlgorithm.h
/usr/include/bullet/BulletCollision/Gimpact/btGImpactMassUtil.h
/usr/include/bullet/BulletCollision/Gimpact/btGImpactQuantizedBvh.h
/usr/include/bullet/BulletCollision/Gimpact/btGImpactShape.h
/usr/include/bullet/BulletCollision/Gimpact/btGenericPoolAllocator.h
/usr/include/bullet/BulletCollision/Gimpact/btGeometryOperations.h
/usr/include/bullet/BulletCollision/Gimpact/btQuantization.h
/usr/include/bullet/BulletCollision/Gimpact/btTriangleShapeEx.h
/usr/include/bullet/BulletCollision/Gimpact/gim_array.h
/usr/include/bullet/BulletCollision/Gimpact/gim_basic_geometry_operations.h
/usr/include/bullet/BulletCollision/Gimpact/gim_bitset.h
/usr/include/bullet/BulletCollision/Gimpact/gim_box_collision.h
/usr/include/bullet/BulletCollision/Gimpact/gim_box_set.h
/usr/include/bullet/BulletCollision/Gimpact/gim_clip_polygon.h
/usr/include/bullet/BulletCollision/Gimpact/gim_contact.h
/usr/include/bullet/BulletCollision/Gimpact/gim_geom_types.h
/usr/include/bullet/BulletCollision/Gimpact/gim_geometry.h
/usr/include/bullet/BulletCollision/Gimpact/gim_hash_table.h
/usr/include/bullet/BulletCollision/Gimpact/gim_linear_math.h
/usr/include/bullet/BulletCollision/Gimpact/gim_math.h
/usr/include/bullet/BulletCollision/Gimpact/gim_memory.h
/usr/include/bullet/BulletCollision/Gimpact/gim_radixsort.h
/usr/include/bullet/BulletCollision/Gimpact/gim_tri_collision.h