It's running through an emulator, and not even a native one at that.
I'm not sure if JSLinux will run Win11, but my experience with using QEMU in emulation mode to run it is that even on hardware a decade newer, it's still slower than this Win2k in the browser.
I'm not sure if JSLinux will run Win11, but my experience with using QEMU in emulation mode to run it is that even on hardware a decade newer, it's still slower than this Win2k in the browser.