According to internal Android documents leaked by 9to5Google, Google's 2021 phone lineup will consist of the Pixel 5a, a folding Pixel device, and two more in-house gadgets.

Given that Pixel phones with an "a" tend to follow the main flagship Pixel phone, it would not be surprising if Google announces the Pixel 5a next year, following the Pixel 5, which is expected to be revealed around October. This would probably take the best parts of the 5th generation Pixel phones and put them in an affordable device. However, the other three devices are more intriguing.

Two of the devices mentioned in the documentation are reportedly codenamed "raven" and "oriole". These are likely to be codenames for the Pixel 6 and Pixel 6 XL, as they are mentioned in the Android documentation.

They could also refer to a new version of the Android Pixel tablet or PixelBook, given that the current models can run Android apps. However, the most likely prediction is that it is the codename for the sixth iteration of the Pixel phone.

The most interesting part of the document is a device codenamed "passport," which is called "foldable." This could be the so-called Pixel Fold foldable phone we have been hearing hints about for some time.

With Samsung's Galaxy Z Fold 2 just unveiled, showing off a foldable phone that looks really attractive, there is certainly room for Google to make a foldable Pixel that challenges Samsung's second-generation foldable phone. And it could be approached from two different angles.

The Pixel Fold could be a truly foldable phone with a flexible display that folds around a clever hinge mechanism, like the Galaxy Fold or Huawei Mate X.

The Pixel Fold could be a phone with a flexible display that folds around a clever hinge mechanism, like the Galaxy Fold or Huawei Mate X. And Google would be more focused on making Android suitable for foldable and dual-screen devices.

Speaking of which, Pixel Fold could make a dual-screen smartphone similar to the Microsoft Surface Duo, without the flexible display. Such a device would not only pave the way for more dual-screen Android apps, but also attempt to mix the pocketable form factor of a cell phone with the screen area of a tablet that can be oriented like a clamshell laptop, Google Apps and services-centric devices could be introduced.

If we're being a bit fanciful, we'd like to see such a Pixel Fold device running traditional Android in phone mode. However, for greater productivity, I would like to see them switch to an improved version of Chrome OS in tablet form.

The Pixel 4a has only just been announced, and the Pixel 5 is being prepared for a fall launch. But a foldable phone built around Google's optimized version of Android for dual-screen devices is certainly an intriguing prospect.