/usr/include/libpwiz/pwiz/analysis/frequency/ is in libpwiz-dev 3.0.4624-6ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libpwiz/pwiz/analysis/frequency/DerivativeTest.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/FrequencyEstimator.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/FrequencyEstimatorPhysicalModel.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/FrequencyEstimatorSimple.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/MagnitudeLorentzian.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/MagnitudeLorentzianTestData.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/ParameterEstimator.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/ParametrizedFunction.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/PeakDetector.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/PeakDetectorMatchedFilter.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/PeakDetectorMatchedFilterTestData.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/PeakDetectorNaive.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/TruncatedLorentzian.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/TruncatedLorentzianEstimator.hpp
/usr/include/libpwiz/pwiz/analysis/frequency/TruncatedLorentzianParameters.hpp