/usr/include/crystalspace-2.0/imesh/ is in libcrystalspace-dev 2.0+dfsg-1build1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/crystalspace-2.0/imesh/animesh.h
/usr/include/crystalspace-2.0/imesh/animnode/
/usr/include/crystalspace-2.0/imesh/animnode/debug.h
/usr/include/crystalspace-2.0/imesh/animnode/ik.h
/usr/include/crystalspace-2.0/imesh/animnode/lookat.h
/usr/include/crystalspace-2.0/imesh/animnode/ragdoll.h
/usr/include/crystalspace-2.0/imesh/animnode/retarget.h
/usr/include/crystalspace-2.0/imesh/animnode/skeleton2anim.h
/usr/include/crystalspace-2.0/imesh/animnode/speed.h
/usr/include/crystalspace-2.0/imesh/bodymesh.h
/usr/include/crystalspace-2.0/imesh/emit.h
/usr/include/crystalspace-2.0/imesh/furmesh.h
/usr/include/crystalspace-2.0/imesh/genmesh.h
/usr/include/crystalspace-2.0/imesh/gmeshanim.h
/usr/include/crystalspace-2.0/imesh/gmeshskel2.h
/usr/include/crystalspace-2.0/imesh/haze.h
/usr/include/crystalspace-2.0/imesh/lghtng.h
/usr/include/crystalspace-2.0/imesh/modifiableterrain.h
/usr/include/crystalspace-2.0/imesh/nullmesh.h
/usr/include/crystalspace-2.0/imesh/object.h
/usr/include/crystalspace-2.0/imesh/objmodel.h
/usr/include/crystalspace-2.0/imesh/particle.h
/usr/include/crystalspace-2.0/imesh/particles.h
/usr/include/crystalspace-2.0/imesh/partsys.h
/usr/include/crystalspace-2.0/imesh/protomesh.h
/usr/include/crystalspace-2.0/imesh/skeleton.h
/usr/include/crystalspace-2.0/imesh/skeleton2.h
/usr/include/crystalspace-2.0/imesh/skeleton2anim.h
/usr/include/crystalspace-2.0/imesh/sprite2d.h
/usr/include/crystalspace-2.0/imesh/sprite3d.h
/usr/include/crystalspace-2.0/imesh/spritecal3d.h
/usr/include/crystalspace-2.0/imesh/terrain.h
/usr/include/crystalspace-2.0/imesh/terrain2.h
/usr/include/crystalspace-2.0/imesh/watermesh.h