Thanks to the method here, with a minor modification for charts, we can get the answer as follows:
ClearAll[chartColors];
chartColors::usage="plotColors[plotType,plotTheme] gives a list of the colors used in a plot when several curves are drawn. Here plotType is, for example, Plot or ListLogPlot while plotTheme may be \"Scientific\", \"Classic\" etc.";
chartColors[chartType_,plotTheme_]:=("ChartDefaultStyle"/.(Method/.Charting`ResolvePlotTheme[plotTheme,chartType]))/.Directive[x_,__]:>x
The output is:

I then tried to look for the name/code of this scheme (something like ColorData[97]
) but didn't get anything.
update:
As @JasonB pointed out, the only difference between ColorData[97]
and the default colour scheme of Histogram
is the yellow colours and their sequence:
cl1=chartColors[Histogram,$PlotTheme];
cl2=ColorData[97,"ColorList"];
Complement[#,Intersection[cl1,cl2]]&/@{cl1,cl2}
The output is:

I cannot understand why WR would break the consistency in default colour schemes of plots/charts functions, in particular the change in colour sequence.
ChartDefaultStyle
. $\endgroup$ColorData
collection. $\endgroup$Charting`ResolvePlotTheme[ChartStyle, Histogram]
adapted slightly from yourPieChart
example leads to a solution here. $\endgroup$