According to a report by Bloomberg citing "people familiar with the situation," Google is referring to Android P, the upcoming update for its Android operating system, as Android ‘Pistachio Ice Cream’ internally. Although that is unlikely to become the release name.
It isn't uncommon for Google to drop the internal code name for the official naming of its latest Android operating system. Android KitKat was referred to internally as 'Key Lime Pie', Nougat had the code name 'New York Cheesecake' and Android Oreo was known internally as 'Oatmeal Cookie' just to name a few, before their official public renaming upon release.
So far, not much is known about the development of Android P aside from it possibly restricting access to hidden APIs, could support call recording (although this is being disputed online) and the next version of Android may even also fully embrace the 'Notch'.
What do you think about the Pistachio Ice Cream name, it sounds a lot like the Ice Cream Sandwich codename from Android 4.0.4 doesn't it?