Notice that the data has a small discontinuity and change in shape above or below 30000 on a 0-65535 scale (i.e. 16 bits of resolution).
My theory is that above are the actual values and how they map to air flow in a stock car as built. I believe that the smooth, evenly spaced curve above 30K represents the theoretical reading vs theoretical air flow.
If I am right, there are calibrations for a LOT more air to come in
than the max that gets in stock. A LOT. Like a blower lot. Like a turbo
lot. Like shove a bunch of air thru the MAF and it has a rough idea how
much is there so the PCM can meter enough fuel to go with it. There is
a discontinuity - the measuring could be spot on with someone who
tunes chips, a dyno and the software tools, but the chip has lots of space reserved for someone to dial in the exact settings and a good starting curve. Even with no programming changes it looks to me like if you shoved a whole bunch of air past the MAF the car just might have an idea what to do with it.
At least that's what it LOOKS like to me.