"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
OS X Snow Leopard Retail Disc Contains Build 10A432
After installing Snow Leopard, pedro10 reports that the retail disc does in fact contain Build 10A432, which had been rumored to be the "Golden Master" version sent to manufacturing for retail distribution. Some unconfirmed reports in recent days had suggested that a different build might have been the shipping version of Snow Leopard, but this appears to not be the case.
As proof, pedro10 posted the above photographs of the Snow Leopard retail packaging.