If a Passbook .pkpass file is saved and opened on a system running OS X 10.8.2, users are shown the digital pass as it would appear on their iPhone. In the bottom right, a button that reads "Add to Passbook" allows users to push that pass to their iPhone, via iCloud.
Passbook support is also contained in Safari and Mail with OS X 10.8.2. If a user receives a Passbook attachment in Mountain Lion Mail, they are presented with a notification that reads "This message contains a Passbook pass."
Users can then click "View Pass" to see the card. From there, users can choose "Add to Passbook," which will add the pass to an iPhone or iPod touch using iCloud.
Users can test the functionality themselves by creating a dummy Passbook file using online tools like PassSource. From there, a .pkpass file can be saved and opened in the latest version of Mountain Lion.
For now, Passbook integration is limited to a handful of applications in iOS 6. But support for .pkpass files could allow stores to provide coupons to users on the Web or via e-mail, and have them quickly and easily sent to a user's iPhone via iCloud, even without a dedicated iOS application.
Passbook-compatible applications began appearing in the iOS App Store on Wednesday alongside the launch of iOS 6. Passbook is one of the most significant new additions to iOS, collecting store cards, gift cards, boarding passes, tickets and other items in a digital wallet.