/usr/include/crystalspace-2.0/ivaria/ is in libcrystalspace-dev 2.0+dfsg-1build1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/crystalspace-2.0/ivaria/bugplug.h
/usr/include/crystalspace-2.0/ivaria/bullet.h
/usr/include/crystalspace-2.0/ivaria/cameramanager.h
/usr/include/crystalspace-2.0/ivaria/collada.h
/usr/include/crystalspace-2.0/ivaria/collider.h
/usr/include/crystalspace-2.0/ivaria/conin.h
/usr/include/crystalspace-2.0/ivaria/conout.h
/usr/include/crystalspace-2.0/ivaria/decal.h
/usr/include/crystalspace-2.0/ivaria/dynamics.h
/usr/include/crystalspace-2.0/ivaria/dynamicsdebug.h
/usr/include/crystalspace-2.0/ivaria/engseq.h
/usr/include/crystalspace-2.0/ivaria/gradient.h
/usr/include/crystalspace-2.0/ivaria/hudmanager.h
/usr/include/crystalspace-2.0/ivaria/icegui.h
/usr/include/crystalspace-2.0/ivaria/keyval.h
/usr/include/crystalspace-2.0/ivaria/mapnode.h
/usr/include/crystalspace-2.0/ivaria/movierecorder.h
/usr/include/crystalspace-2.0/ivaria/ode.h
/usr/include/crystalspace-2.0/ivaria/pagingformer.h
/usr/include/crystalspace-2.0/ivaria/pmeter.h
/usr/include/crystalspace-2.0/ivaria/profile.h
/usr/include/crystalspace-2.0/ivaria/reporter.h
/usr/include/crystalspace-2.0/ivaria/script.h
/usr/include/crystalspace-2.0/ivaria/sequence.h
/usr/include/crystalspace-2.0/ivaria/simpleformer.h
/usr/include/crystalspace-2.0/ivaria/softanim.h
/usr/include/crystalspace-2.0/ivaria/stdrep.h
/usr/include/crystalspace-2.0/ivaria/terraform.h
/usr/include/crystalspace-2.0/ivaria/translator.h
/usr/include/crystalspace-2.0/ivaria/view.h
/usr/include/crystalspace-2.0/ivaria/xwindow.h