The largest issuer of private label cards in the U.S., Synchrony Financial, has introduced a plug-in its retailer customers can add to their mobile apps that lets private label credit cardholders manage their card accounts as well as shop and redeem rewards. JCPenney and Dick’s Sporting Goods are among the first users. Card account management features include viewing balance and purchase activity, checking available credit, and making payments. Everything is done with a smartphone. Currently, no retailer clients use the Synchrony plug-in (SyPi) for in-app or in-store purchases. SyPi, whic...