Google is working on an Android firmware that will be made for virtual machines. It will be the Linux based Android distribution for virtual machines called MicroDroid, which can also be called the minimal Android version for virtual machines. As per the commit description, MicroDroid is the “Stripped down version of the Generic Android System Image” also known as GSI.
It is being said that this project is aimed to allow for a running minimal version of Android. It will allow virtualizing of an individual android app contradictory to provide the full secondary desktop environment.
[Source]