No link, it's stockcharts APC. You can try recreating it using the settings indicated on the chart, but this is one of the drawbacks of APC charts. Can't link to it.

The mane panes in the center of the chart show $NYUD (on the left side) and $NAUD (on the right side). The two panes at the bottom of the chart show up volume divided by down volume and vice versa. These are all breadth indicators. When breadth is strong in a move, it tends to lend it credence. 

$NAUD subtracts down volume from up volume. The indicator I mentioned $NAUPV:$NADNV divides up volume by down volume. 25:1 is really, really, really strong. It has since declined to 13:1 which is just really, really strong. When moves have a ratio 4:1 or 6:1, that's strong and gives a sense it can be trusted. But don't get me wrong, it's no guarantee. There are no guarantees (except maybe the BPT SPY systems  ). But it's nice to have breadth on your side, and one might consider a move suspect when breadth doesn't endorse it.