That was added by Microsoft recently to that page. Things are evolving rapidly. The discussion is mostly here: January Intel Meltdown Patches
I think that setting may only be applicable if the host machine is running Hyper-V, so I think it doesn’t need applied otherwise. I haven’t tested this at all: https://github.com/jgstew/bigfix-content/blob/master/fixlet/Enable%20Meltdown%20Mitigations%20-%20MinVmVersionForCpuBasedMitigations%20-%20Windows.bes