> but they need a native seL4/Linux if they want to honestly claim they are improving systems' security with their capability model.
Are you using "seL4/Linux" in the style of "GNU/Linux"? Because then it should be "GNU/seL4" - that would describe an OS exposing the GNU core utilities on top of the seL4 kernel. There's no way to mix the Linux kernel with the seL4 kernel, other than using one to run VMs of the other.
I mean something like MkLinux with seL4 at its core with all processes and drivers running under seL4 and taking advantage of the seL4 capability model.
It doesn't even have to be a Linux–compatible OS in theory although that is the standard to beat.
https://en.wikipedia.org/wiki/L4Linux