In Standalone Chart component, text and interior information for a point can be bound from a datasource other than the x and y values. The implicit named parameter context can be used to access the aggregate values within the Template To retrieve aggregate values inside the template, type cast the context as ChartPointDataInfo. The context attribute can also be used to modify the name of this implicit parameter
Currently, Pivot chart doesn't have an option for template in PivotChartDataLabels. Need to implement the template support in Pivot Chart.