/usr/include/simgear/math/ is in libsimgear-dev 3.4.0-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/simgear/math/SGBox.hxx
/usr/include/simgear/math/SGCMath.hxx
/usr/include/simgear/math/SGGeoc.hxx
/usr/include/simgear/math/SGGeod.hxx
/usr/include/simgear/math/SGGeodesy.hxx
/usr/include/simgear/math/SGGeometry.hxx
/usr/include/simgear/math/SGGeometryFwd.hxx
/usr/include/simgear/math/SGIntersect.hxx
/usr/include/simgear/math/SGLimits.hxx
/usr/include/simgear/math/SGLineSegment.hxx
/usr/include/simgear/math/SGLocation.hxx
/usr/include/simgear/math/SGMath.hxx
/usr/include/simgear/math/SGMathFwd.hxx
/usr/include/simgear/math/SGMatrix.hxx
/usr/include/simgear/math/SGMisc.hxx
/usr/include/simgear/math/SGPlane.hxx
/usr/include/simgear/math/SGQuat.hxx
/usr/include/simgear/math/SGRay.hxx
/usr/include/simgear/math/SGRect.hxx
/usr/include/simgear/math/SGSphere.hxx
/usr/include/simgear/math/SGTriangle.hxx
/usr/include/simgear/math/SGVec2.hxx
/usr/include/simgear/math/SGVec3.hxx
/usr/include/simgear/math/SGVec4.hxx
/usr/include/simgear/math/beziercurve.hxx
/usr/include/simgear/math/interpolater.hxx
/usr/include/simgear/math/leastsqs.hxx
/usr/include/simgear/math/sg_geodesy.hxx
/usr/include/simgear/math/sg_random.h
/usr/include/simgear/math/sg_types.hxx