/usr/include/freefoam/engine/ is in libfreefoam-dev 0.1.0+dfsg+1-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/freefoam/engine/StCorr.H
/usr/include/freefoam/engine/createEngineMesh.H
/usr/include/freefoam/engine/createEngineTime.H
/usr/include/freefoam/engine/engineMesh.H
/usr/include/freefoam/engine/enginePiston.H
/usr/include/freefoam/engine/engineTime.H
/usr/include/freefoam/engine/engineValve.H
/usr/include/freefoam/engine/fvMotionSolverEngineMesh.H
/usr/include/freefoam/engine/ignite.H
/usr/include/freefoam/engine/ignition.H
/usr/include/freefoam/engine/ignitionSite.H
/usr/include/freefoam/engine/layeredEngineMesh.H
/usr/include/freefoam/engine/staticEngineMesh.H
/usr/include/freefoam/engine/valveBank.H