You click on it and SAP server explodes immediately. Seriously - why not just try it in a test system? I can assure you there are no buttons in SAP that cause explosions (although would be kind of cool).
Also Google -> 'VA01 propose item site:sap.com' -> over 1000 entries found, including the one from where Enrique copy-pasted but somehow forgot to include the source: how to configure item proposal