TLegend *leg = new TLegend(0.6,0.6,0.9,0.9); //create a new TLegend object leg->SetLineColor(kBlack); //set the border color of the legend to blackIn this example, a new TLegend object is created, specifying its position on the plot. The SetLineColor() function is then called on the legend object, setting the border color of the legend to black. Overall, the TLegend SetLineColor() function is useful for customizing the appearance of legends in ROOT plots.