This is Google's Indoor Maps product. It is a different product from Street View. It has been around in beta for a while now (3-4 years?). Google is interested in floor plans for airports, stadiums, malls. Similar to Street View, that content can be uploaded by users or created by Google teams. Read the page you found for more info. Getting floor plans uploaded when doing Street View export is not supported by Google now, but who knows what the future may bring.