public static float getBorderFocusWidth( JComponent c ) {
		FlatBorder border = getOutsideFlatBorder( c );
		return (border != null)
			? UIScale.scale( (float) border.getFocusWidth( c ) )
			: 0;
	}
Returns the scaled thickness of the outer focus border for the given component.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatUIUtils.java