Collabora is a software development and consulting company based in the United Kingdom. In a blog post, the company described its new "experimental containerized Android environment," which allows Android apps to run in floating windows alongside native applications on desktop Linux.
You can read all the technical details at the source link below, but put simply, 'SPURV' creates a virtual Android device on your Linux computer, much like Bluestacks and other similar tools. There are various components of SPURV that allow the Android environment to play audio, connect to networks, and display hardware-accelerated graphics through the underlying Linux system.
The most interesting part is 'SPURV HWComposer,' which renders Android applications in windows, alongside the windows from native Linux applications. This is what sets SPURV apart from (most) other methods of running Android on a computer. For this to work, the Linux desktop has to be using the Wayland display server (some Linux-based OSes use X11).
Pre-built binaries for SPURV are not currently available — you have to build it yourself from the source code. Still, it's an interesting proof-of-concept, and hopefully someone turns it into a full-featured product.