Here's the link from the article: https://alyssa.is/using-virtio-wl/

It doesn't really have a better name. It was written by Google to allow Android apps to run inside a VM on ChromeOS. Although it does work with mainline Linux, Google is understandably not motivated to invest effort in branding virtwl.ko with a non-cryptic name, or marketing it as its own project independent of ChromeOS. AFIAK nobody outside of Google was using it until Alyssa (same person responsible for the panfrost awesomeness) got it working on Linux.

As for what it does?

Wayland clients and servers must (a) run on the same physical machine (b) as processes on the same kernel. Virtwl.ko removes requirement (b), allowing the client to be inside of a VM.