Each datapoint on https://performance.mozilla.org/ should link back to some changelog :
Ideally, the changelog is to a specific Nightly build. If that is not possbile, then the datapoint should link to all the bugs that landed in that day. That way, a person looking at a change in the graphs will atleast have 1 days worth of bugs to look through and they can narrow it down to a manageable list.
Without this functionality, IMHO the usefulness of the dashboard will be limited.