> The Muen Separation Kernel is the world’s first Open Source microkernel that has been formally proven to contain no runtime errors at the source code level.
I had the impression seL4 was the first microkernel formally proven to be secure.
Also, no runtime errors is quite different from secure, and at the source code level (which I think applies to both OSes) leaves room for compiler, linker, or standard library to introduce issues.
I had the impression seL4 was the first microkernel formally proven to be secure.