Which MNI152 space is used within FreeSurfer? Is it the MNI152 nonlinear 6-th generation (as in, for example, FSL), or another one, like MNI152 nonlinear 2009a, 2009b or 2009c?

I wasn’t able to find this information in the fswiki. 

I checked https://surfer.nmr.mgh.harvard.edu/fswiki/CoordinateSystems and the documentation of certain functions, such as mri_cvs_register.