/usr/include/eigen3/unsupported/Eigen/src/ is in libeigen3-dev 3.2.2-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/eigen3/unsupported/Eigen/src/AutoDiff/
/usr/include/eigen3/unsupported/Eigen/src/AutoDiff/AutoDiffJacobian.h
/usr/include/eigen3/unsupported/Eigen/src/AutoDiff/AutoDiffScalar.h
/usr/include/eigen3/unsupported/Eigen/src/AutoDiff/AutoDiffVector.h
/usr/include/eigen3/unsupported/Eigen/src/BVH/
/usr/include/eigen3/unsupported/Eigen/src/BVH/BVAlgorithms.h
/usr/include/eigen3/unsupported/Eigen/src/BVH/KdBVH.h
/usr/include/eigen3/unsupported/Eigen/src/FFT/
/usr/include/eigen3/unsupported/Eigen/src/FFT/ei_fftw_impl.h
/usr/include/eigen3/unsupported/Eigen/src/FFT/ei_kissfft_impl.h
/usr/include/eigen3/unsupported/Eigen/src/IterativeSolvers/
/usr/include/eigen3/unsupported/Eigen/src/IterativeSolvers/ConstrainedConjGrad.h
/usr/include/eigen3/unsupported/Eigen/src/IterativeSolvers/DGMRES.h
/usr/include/eigen3/unsupported/Eigen/src/IterativeSolvers/GMRES.h
/usr/include/eigen3/unsupported/Eigen/src/IterativeSolvers/IncompleteCholesky.h
/usr/include/eigen3/unsupported/Eigen/src/IterativeSolvers/IncompleteLU.h
/usr/include/eigen3/unsupported/Eigen/src/IterativeSolvers/IterationController.h
/usr/include/eigen3/unsupported/Eigen/src/IterativeSolvers/MINRES.h
/usr/include/eigen3/unsupported/Eigen/src/IterativeSolvers/Scaling.h
/usr/include/eigen3/unsupported/Eigen/src/KroneckerProduct/
/usr/include/eigen3/unsupported/Eigen/src/KroneckerProduct/KroneckerTensorProduct.h
/usr/include/eigen3/unsupported/Eigen/src/MatrixFunctions/
/usr/include/eigen3/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h
/usr/include/eigen3/unsupported/Eigen/src/MatrixFunctions/MatrixFunction.h
/usr/include/eigen3/unsupported/Eigen/src/MatrixFunctions/MatrixFunctionAtomic.h
/usr/include/eigen3/unsupported/Eigen/src/MatrixFunctions/MatrixLogarithm.h
/usr/include/eigen3/unsupported/Eigen/src/MatrixFunctions/MatrixPower.h
/usr/include/eigen3/unsupported/Eigen/src/MatrixFunctions/MatrixSquareRoot.h
/usr/include/eigen3/unsupported/Eigen/src/MatrixFunctions/StemFunction.h
/usr/include/eigen3/unsupported/Eigen/src/MoreVectorization/
/usr/include/eigen3/unsupported/Eigen/src/MoreVectorization/MathFunctions.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/HybridNonLinearSolver.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/LevenbergMarquardt.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/chkder.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/covar.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/dogleg.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/fdjac1.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/lmpar.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/qrsolv.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/r1mpyq.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/r1updt.h
/usr/include/eigen3/unsupported/Eigen/src/NonLinearOptimization/rwupdt.h
/usr/include/eigen3/unsupported/Eigen/src/NumericalDiff/
/usr/include/eigen3/unsupported/Eigen/src/NumericalDiff/NumericalDiff.h
/usr/include/eigen3/unsupported/Eigen/src/Polynomials/
/usr/include/eigen3/unsupported/Eigen/src/Polynomials/Companion.h
/usr/include/eigen3/unsupported/Eigen/src/Polynomials/PolynomialSolver.h
/usr/include/eigen3/unsupported/Eigen/src/Polynomials/PolynomialUtils.h
/usr/include/eigen3/unsupported/Eigen/src/Skyline/
/usr/include/eigen3/unsupported/Eigen/src/Skyline/SkylineInplaceLU.h
/usr/include/eigen3/unsupported/Eigen/src/Skyline/SkylineMatrix.h
/usr/include/eigen3/unsupported/Eigen/src/Skyline/SkylineMatrixBase.h
/usr/include/eigen3/unsupported/Eigen/src/Skyline/SkylineProduct.h
/usr/include/eigen3/unsupported/Eigen/src/Skyline/SkylineStorage.h
/usr/include/eigen3/unsupported/Eigen/src/Skyline/SkylineUtil.h
/usr/include/eigen3/unsupported/Eigen/src/SparseExtra/
/usr/include/eigen3/unsupported/Eigen/src/SparseExtra/BlockOfDynamicSparseMatrix.h
/usr/include/eigen3/unsupported/Eigen/src/SparseExtra/DynamicSparseMatrix.h
/usr/include/eigen3/unsupported/Eigen/src/SparseExtra/MarketIO.h
/usr/include/eigen3/unsupported/Eigen/src/SparseExtra/MatrixMarketIterator.h
/usr/include/eigen3/unsupported/Eigen/src/SparseExtra/RandomSetter.h
/usr/include/eigen3/unsupported/Eigen/src/Splines/
/usr/include/eigen3/unsupported/Eigen/src/Splines/Spline.h
/usr/include/eigen3/unsupported/Eigen/src/Splines/SplineFitting.h
/usr/include/eigen3/unsupported/Eigen/src/Splines/SplineFwd.h