/usr/include/casacore/scimath/Fitting/ is in casacore-dev 2.2.0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/casacore/scimath/Fitting/FitGaussian.h
/usr/include/casacore/scimath/Fitting/FitGaussian.tcc
/usr/include/casacore/scimath/Fitting/FittingProxy.h
/usr/include/casacore/scimath/Fitting/GenericL2Fit.h
/usr/include/casacore/scimath/Fitting/GenericL2Fit.tcc
/usr/include/casacore/scimath/Fitting/LSQFit.h
/usr/include/casacore/scimath/Fitting/LSQFit2.tcc
/usr/include/casacore/scimath/Fitting/LSQMatrix.h
/usr/include/casacore/scimath/Fitting/LSQTraits.h
/usr/include/casacore/scimath/Fitting/LSQaips.h
/usr/include/casacore/scimath/Fitting/LSQaips.tcc
/usr/include/casacore/scimath/Fitting/LinearFit.h
/usr/include/casacore/scimath/Fitting/LinearFit.tcc
/usr/include/casacore/scimath/Fitting/LinearFitSVD.h
/usr/include/casacore/scimath/Fitting/LinearFitSVD.tcc
/usr/include/casacore/scimath/Fitting/NonLinearFit.h
/usr/include/casacore/scimath/Fitting/NonLinearFit.tcc
/usr/include/casacore/scimath/Fitting/NonLinearFitLM.h
/usr/include/casacore/scimath/Fitting/NonLinearFitLM.tcc