As noticed by Tom Warren of The Verge and reported by iMore, Microsoft has created a method that takes the data from a Passbook file and converts it into a card that is imported into Microsoft Wallet.
Windows Phone 8.1 supports Apple's Passbook natively. I've been using it for flights. Works perfectly pic.twitter.com/MFScqvEVU7— Tom Warren (@tomwarren) April 14, 2014
Passbook debuted in 2012 and was one of the major new apps bundled in iOS 6. The digital wallet permitted companies to store tickets, loyalty cards, coupons, gift cards and more in a centralized location on a user's iPhone