One of the biggest problems plaguing the Android ecosystem had been fragmentation in terms of OS updates. Google tried to solve that with Project Treble, which they announced back in 2017. Now with a mandate that all modern Android devices must support Project Treble, Google has ensured to a degree that devices other than Google's Pixel can receive the future Android updates and Betas (such as in the case of Android Pie) right alongside Google’s own devices.
A critical part of Project Treble is the Generic System Image (GSI), the purest form of Android built from Android Open Source Project (AOSP) and completely devoid of any manufacturer specific customizations. Google requires that the GSI be bootable on top of the existing OEM implementation. Google also mandates that OEMs run a series of tests such as CTS-on-GSI (Compatibility Test Suite on Generic System Image) and VTS (Vendor Test Suite) to make sure that basic hardware functionality works when running a GSI. What this means is that even before the source code is made available to AOSP, the GSI of future Android builds could theoretically run on certified devices. But there’s more.
According to XDA, speaking at this year’s Android Dev Summit, Hung-ying Tyan from Google’s Project Treble team held a talk titled “Understand the impact of Generic System Images (GSI).” During his talk, he said, “GSI is the central piece in Treble compliance. We feel that it has a lot more potential than that. We set out a goal to make GSI be more accessible and useful, not just for device makers but also the general public including app developers like you and even consumers. An important first step toward that goal is to make GSI available in AOSP. So for this, we have published pie-gsi in AOSP. So now you can download and build pie-gsi today. We are also exploring ways to make future GSI available earlier than the release of next Android version. So you will be able to try out next Android version earlier over GSI. And at the same time we can also get early feedback from you, so the benefit is mutual. So please stay tuned for our further announcement on this.” – Hung-ying Tyan, Google.
Essentially, all this alludes to the possibility of being able to try out Android Q even before its AOSP release, even before the Developer or Public betas are released. Of course, this build would be devoid of any OEM customisations such as those made by Google to the Pixel ROM or those made by Samsung, OnePlus, Huawei and others. However, this kind of release would most benefit developers (and consequently users) as they would be able to test their apps on the future build of Android far sooner than normal, which would mean greater compatibility with future versions of Android on release day.