Preview exposure value NEF vs JPEG

[ohdeeremee]

Help me learn something, please.

Nikon, D80, I did JPEG + Raw, EV = -3.0.
XnView:
Jpeg as expected, thumbnail dark, preview dark (as expected). Histogram far left as expected.

NEF (raw file) Thumbnail dark (have Use Embedded Thumbnails set) (as expected, Thumbnail is a JPEG). Histogram spread out as if proper exposure.

Preview appears to be at EV=0 level of exposure. Not dark. As if "Auto Exposure" is set. I expected the preview to be dark also.

Adobe Camera Raw shows dark, histogram far left. (as expected)

Did I miss some option? or is this the way it works?

Maybe this is a Nikon question, but at what point in the data stream is the EV values applied?


Thanks
George