Why is this extension called Smstateen?

[lbmeng]

The spec proposes adding several machine level CSRs, so according to chapter 27 ISA Extension Naming Conventions of riscv-spec-20191213.pdf,

27.9 Machine-level Instruction-Set Extensions
Standard machine-level instruction-set extensions are prefixed with the three letters “Zxm”.

Shouldn't the extension name be prefixed with "Zxm", instead of "S"?

[lbmeng]

When looking at the latest riscv-isa-manual, it doesn't change anything in the extension naming conventions.

But I just found out an issue was filed against extension names here about a year ago:
riscv/riscv-isa-manual#688
which might possibly partially explain why this extension is called "Smstateen"?