/usr/include/Wt/Chart/ is in libwt-dev 3.3.6+dfsg-1.1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/Wt/Chart/WAbstractChart
/usr/include/Wt/Chart/WAbstractChartImplementation
/usr/include/Wt/Chart/WAbstractChartModel
/usr/include/Wt/Chart/WAbstractColorMap
/usr/include/Wt/Chart/WAbstractDataSeries3D
/usr/include/Wt/Chart/WAbstractGridData
/usr/include/Wt/Chart/WAxis
/usr/include/Wt/Chart/WAxisSliderWidget
/usr/include/Wt/Chart/WCartesian3DChart
/usr/include/Wt/Chart/WCartesianChart
/usr/include/Wt/Chart/WChart2DImplementation
/usr/include/Wt/Chart/WChart3DImplementation
/usr/include/Wt/Chart/WChartGlobal
/usr/include/Wt/Chart/WChartPalette
/usr/include/Wt/Chart/WDataSeries
/usr/include/Wt/Chart/WEquidistantGridData
/usr/include/Wt/Chart/WGridData
/usr/include/Wt/Chart/WLegend
/usr/include/Wt/Chart/WLegend3D
/usr/include/Wt/Chart/WPieChart
/usr/include/Wt/Chart/WScatterData
/usr/include/Wt/Chart/WSelection
/usr/include/Wt/Chart/WStandardChartProxyModel
/usr/include/Wt/Chart/WStandardColorMap
/usr/include/Wt/Chart/WStandardPalette