Microsoft has rolled out another new Dev Channel test build to Insider testers today, March 24. Windows 10 Build 21343 makes some changes to the underlying sandbox technology in the operating system and adds new File Explorer icons.
The Windows Sandbox and Microsoft Defender Application Guard (MDAG) both use container technology that is built into Windows 10. Up to this point, the container runtime matched that of the host OS. But starting witht his build, Microsoft is switching this out with a new lighter-weight runtime that's optimized for container scenarios that Microsoft officials say they are expecting to offer better performance without affecting compatibility.
Build 21343 also includes a substantial number of fixes and updates, as well as Known Issues (which anyone using their machines for gaming purposes definitely should check out).