Google is already lining up some new hardware for its October 4th event, but the company may also have important new software details to announce soon as well. An anonymous source states that users have been running early builds of an Android/Chrome OS hybrid, known as “Andromeda”, on the HTC Nexus 9, and that Google has been internally testing its new OS.

An Android 7.0 Nougat AOSP file labelled “SurfaceCompositionTest.java” appears to be some sort of graphics performance test designed for Andromeda. The file specifically mentions that “Andromeda devices require higher performance score”, and suggests that a minimum graphics score of 8.0 is required to run the OS. For comparison, a score of just 4.0 is required to run Android, and the Nexus 9 scores an 8.8.

It seems unlikely that Google would debut its new operating system on the old Nexus 9. Instead, the tablet may be being used for testing due to its more unique and powerful Tegra K1 processor, with Denver CPU cores and Kepler DX1 GPU. The fact that this code appears in the general ASOP directory also means that Andromeda could be planned for a wider range of devices.

A second hint also points to the free form window management feature that is hidden away inside Android Nougat. Perhaps this feature will makes its official debut with Andromeda.

The source code also suggests that this isn’t a small code or feature insertion, but requires a complete rebuilding of the system image. This is hinted at by the fact that part of the ASOP page mentions a “Flushed Nexus 9 device using volantis and volantis-andromeda images”.

The Andromeda hybrid OS has been in and out of rumors and leaks for a while now, but we don’t know the exact make up of the new OS yet. An old report from the Wall Street Journal suggests that Google is planning to “fold” Chrome OS into Android, which would make it quite different to Google’s efforts to bring Android apps to Chromebooks.

The growing number of leaks suggest that Google is planning to release a new OS with superior cross-platform capabilities for some future mobile devices, most likely aimed at the tablet and 2-in-1 market. Reports have previously pointed to a potential 2017 release, but if Hiroshi Lockheimer’s recent Tweet is anything to go by, Google might just tease us with the new OS next Tuesday.