/usr/include/ncarg/ncl/ is in libncarg-dev 6.3.0-6build1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ncarg/ncl/AdvancedFileSupport.h
/usr/include/ncarg/ncl/ApiRecords.h
/usr/include/ncarg/ncl/AttSupport.h
/usr/include/ncarg/ncl/DataSupport.h
/usr/include/ncarg/ncl/FileSupport.h
/usr/include/ncarg/ncl/HluClasses.h
/usr/include/ncarg/ncl/NclAdvancedFile.h
/usr/include/ncarg/ncl/NclAdvancedFileStructure.h
/usr/include/ncarg/ncl/NclAdvancedGroup.h
/usr/include/ncarg/ncl/NclApi.h
/usr/include/ncarg/ncl/NclAtt.h
/usr/include/ncarg/ncl/NclBuiltInSupport.h
/usr/include/ncarg/ncl/NclBuiltIns.h
/usr/include/ncarg/ncl/NclCallBacksI.h
/usr/include/ncarg/ncl/NclCoordVar.h
/usr/include/ncarg/ncl/NclData.h
/usr/include/ncarg/ncl/NclDataDefs.h
/usr/include/ncarg/ncl/NclDriver.h
/usr/include/ncarg/ncl/NclFile.h
/usr/include/ncarg/ncl/NclFileInterfaces.h
/usr/include/ncarg/ncl/NclGroup.h
/usr/include/ncarg/ncl/NclHDF.h
/usr/include/ncarg/ncl/NclList.h
/usr/include/ncarg/ncl/NclMdInc.h
/usr/include/ncarg/ncl/NclMultiDValData.h
/usr/include/ncarg/ncl/NclMultiDValHLUObjData.h
/usr/include/ncarg/ncl/NclMultiDVallistData.h
/usr/include/ncarg/ncl/NclMultiDValnclfileData.h
/usr/include/ncarg/ncl/NclOneDValCoordData.h
/usr/include/ncarg/ncl/NclOptions.h
/usr/include/ncarg/ncl/NclType.h
/usr/include/ncarg/ncl/NclTypebyte.h
/usr/include/ncarg/ncl/NclTypechar.h
/usr/include/ncarg/ncl/NclTypedouble.h
/usr/include/ncarg/ncl/NclTypefloat.h
/usr/include/ncarg/ncl/NclTypeint.h
/usr/include/ncarg/ncl/NclTypeint64.h
/usr/include/ncarg/ncl/NclTypelist.h
/usr/include/ncarg/ncl/NclTypelogical.h
/usr/include/ncarg/ncl/NclTypelong.h
/usr/include/ncarg/ncl/NclTypeobj.h
/usr/include/ncarg/ncl/NclTypeshort.h
/usr/include/ncarg/ncl/NclTypestring.h
/usr/include/ncarg/ncl/NclTypeubyte.h
/usr/include/ncarg/ncl/NclTypeuint.h
/usr/include/ncarg/ncl/NclTypeuint64.h
/usr/include/ncarg/ncl/NclTypeulong.h
/usr/include/ncarg/ncl/NclTypeushort.h
/usr/include/ncarg/ncl/NclVar.h
/usr/include/ncarg/ncl/Symbol.h
/usr/include/ncarg/ncl/TypeSupport.h
/usr/include/ncarg/ncl/VarSupport.h
/usr/include/ncarg/ncl/defs.h