code: protected void updateTooltip()
  	{
  		if (slot.getItemStack().isEmpty())
  		{
  			tooltip = defaultTooltip;
  			return;
  		}
  
  		List<String> lines = slot	.getItemStack()
  									.getTooltip(Utils.getClientPlayer(),
  												Minecraft.getMinecraft().gameSettings.advancedItemTooltips	? ITooltipFlag.TooltipFlags.ADVANCED
  																											: ITooltipFlag.TooltipFlags.NORMAL);
  
  		String text = lines.stream().collect(Collectors.joining(TextFormatting.RESET + "\n" + TextFormatting.GRAY));
  		//		lines.set(0, slot.getItemStack().getRarity().rarityColor + lines.get(0));
  		//		for (int i = 1; i < lines.size(); i++)
  		//			lines.set(i, TextFormatting.GRAY + lines.get(i));
  
  		tooltip = new UITooltip(slot.getItemStack().getRarity().rarityColor + text);
  	}
docs: Updates the {@link UITooltip} of this {@link UISlot} based on the contained ItemStack.<br>
  If no ItemStack is present in slot, revert the tooltip back to default one.