The only implementation built by Microsoft of any standard in WSL is the bridge that provides a Linux kernel interface (it proxies Linux syscalls to the NT kern

The only implementation built by Microsoft of any standard in WSL is the bridge that provides a Linux kernel interface (it proxies Linux syscalls to the NT kernel). But their only goal there is to support Linux userspace, so it would be rather pointless to add extra syscalls or extend the existing ones. (And besides, they haven't even finished implementing all of the system calls...) For WSL 2, they're taking the Linux kernel whosesale and dropping it into a VM in Hyper-V. If anything, they're backing away from anything that could be construed as a possible EEE.