Focus peaking and magnification can only be done in the center, which is just silly.
It would be an oversight of Leica-esque proportions if this were true, Dave.
When not in AF mode, turning the lens focus ring invokes focus magnification and shows the red focus box, and the VF provides arrows so the rear spin dial can be used to move the focus spot around, with peaking available. It's fast and effective.
The really neat part of this feature, besides it being so readily available and having peaking built in, is that the area of the frame it can magnify is.....
100%.
So you can separate (i) composition refinement, then (ii) focus mag on
any part of the frame.
It's even better than the (highly adjustable)
flexi spot in AF, which only covers maybe 90% of the frame - still way better than the DSLRs the 'pros' will tell you are so great. ;-)
What I like also is that this feature encourages photographers
to not be lazy and rely on the old focus then recompose hack, which works so poorly in modern high res photography at wider apertures.
Pity the poor old DSLR users, who have been systematically dumbed down by their brands.
The Nikon D810 looks like it is up to around 30-35% of frame coverage for the only mode it works OK in - auto focus:
https://photographylife.com/reviews/nikon-d750/2 (scroll half way down to see the pattern)
That is something the RX1 (or a7 series) owner would, of course, find totally unacceptable.