Mashable reports early builds of Apple's upcoming OS X 10.9 reveal Siri and Apple Maps as new functionality:
Both features are in early stages of testing, and it’s unclear whether they’ll ever reach the final product. This especially goes for Siri, 9to5Mac argues, which might ultimately available only on some devices. In the iOS world, Siri is only available on newer iPhones, iPads and iPod touches.
As far as functionality goes, Siri could (obviously) be used to perform voice commands on Macs, and Maps could enable developers to embed a map into their Mac App Store apps. Apple could also looking to create its own, standalone Apple Maps desktop app, as well as integrate the map into some of the OS’s features.