/usr/include/freefoam/dsmc/ is in libfreefoam-dev 0.1.0+dfsg+1-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/freefoam/dsmc/BinaryCollisionModel.C
/usr/include/freefoam/dsmc/BinaryCollisionModel.H
/usr/include/freefoam/dsmc/DsmcBaseCloud.H
/usr/include/freefoam/dsmc/DsmcCloudI_.H
/usr/include/freefoam/dsmc/DsmcCloud_.C
/usr/include/freefoam/dsmc/DsmcCloud_.H
/usr/include/freefoam/dsmc/DsmcParcelIO.C
/usr/include/freefoam/dsmc/DsmcParcelI_.H
/usr/include/freefoam/dsmc/DsmcParcel_.C
/usr/include/freefoam/dsmc/DsmcParcel_.H
/usr/include/freefoam/dsmc/FreeStream.C
/usr/include/freefoam/dsmc/FreeStream.H
/usr/include/freefoam/dsmc/InflowBoundaryModel.C
/usr/include/freefoam/dsmc/InflowBoundaryModel.H
/usr/include/freefoam/dsmc/LarsenBorgnakkeVariableHardSphere.C
/usr/include/freefoam/dsmc/LarsenBorgnakkeVariableHardSphere.H
/usr/include/freefoam/dsmc/MaxwellianThermal.C
/usr/include/freefoam/dsmc/MaxwellianThermal.H
/usr/include/freefoam/dsmc/MixedDiffuseSpecular.C
/usr/include/freefoam/dsmc/MixedDiffuseSpecular.H
/usr/include/freefoam/dsmc/NewBinaryCollisionModel.C
/usr/include/freefoam/dsmc/NewInflowBoundaryModel.C
/usr/include/freefoam/dsmc/NewWallInteractionModel.C
/usr/include/freefoam/dsmc/NoInflow.C
/usr/include/freefoam/dsmc/NoInflow.H
/usr/include/freefoam/dsmc/SpecularReflection.C
/usr/include/freefoam/dsmc/SpecularReflection.H
/usr/include/freefoam/dsmc/VariableHardSphere.C
/usr/include/freefoam/dsmc/VariableHardSphere.H
/usr/include/freefoam/dsmc/WallInteractionModel.C
/usr/include/freefoam/dsmc/WallInteractionModel.H
/usr/include/freefoam/dsmc/dsmcCloud.H
/usr/include/freefoam/dsmc/dsmcParcel.H