If you klick on a driver, his page comes up.
https://igpmanager.com/play/?url=team-driver/89268
For the chart at the top right, data gets requested from server. This request has the param "id" two times. https://igpmanager.com/play/content/misc/igp/xml/xml_driver.php?id=7826&id=89268
The first one seems to be obsolete: it has no effect (changing or deleting).
System:
Chrome on Win7 64bit