Most Apple code names aren't public. Mac software, be it OS X Jaguar or macOS Sierra is the lone exception. The rest, including project code names like the switch to Intel (Marklar), iPhone (Purple), Apple Watch (Gizmo), and the upcoming (Titan), operating systems like iOS (ski resorts) and watchOS (beaches), and apps and services like Safari (Alexander), CarPlay (Stark), Spotlight (Matador), iCloud (Ubiquity), and Apple Music (Fuse), are all internal.
Once they've shipped, though, the code names often come out. And while knowing the names doesn't really matter, for any fan of legend and lore, discovering them is still pretty cool.