Unless I'm mistaken, WSL to WSL2 was massive change in complete architecture, with WSL2 now requiring virtualization and making your host-OS run on top of hypervisor, with potential tradeoffs not many users are typically aware of. Basically, WSL and WSL2 were different beasts entirely :)
Was there anything that big or note-worthy from WSL2 to WSL3? Or just a natural evolution/upgrade?
The big addition here is the support for containers. The app now provides a simple way to run containers directly. Underneath the hood, there's still a kernel running on a VM, though. There's also some improvements to the filesystem layer, a kernel upgrade, etc.
This article[0] does a nice job explaining it.
[0] https://zenn.dev/yohakucode/articles/wsl3-wsl2-wslc-update
virtiofs is the biggest change, it was experimental in 2.x. It doesn’t affect my application, but most new users who want to share files between windows + Linux will see a huge bump.