The white and brown were combined during the pin drafting process, which is when the roving is combed one additional time so that it is extra smooth and lofty. The yarn should spin up as a variegated brown and white.
There is very little VM, and what is there is easily picked out as you spin.
The last picture is of some of my homespun using a drop spindle so you can see the kind of candy-striped yarn this roving can produce. I'm not the best spinner, so I'm sure your yarn will be far more consistent than mine. :)
Thanks for looking!