It runs ontop of the libkrun vmm forked with optimizations, which is the underlying lib powering podman as well.
open source, will contribute upstream when possible: https://github.com/smol-machines/libkrun
But it seems more like a completely different way to run isolated workloads?
It also has container-inages support built-in with crun so you can create a VM with a container running by default.
You can also just... run docker inside of it.
It provides kernel isolation for running untrusted code which is a security boundary that traditional containers can't guarantee.
I'm engaged with a third party security penetration company for their review, and will be happy to share it publicly when it is available.