Looks like the sensor saturation tops out well below the 14-bit maximum reported by libraw, ~13542 in the red channel. Here are the stats for this image:
channels:
rmin: 0.030563 rmax: 0.206375
g1min: 0.030731 g1max: 0.206161
g2min: 0.030762 g2max: 0.204697
bmin: 0.030563 bmax: 0.203796
channel means:
rmean: 0.045369
g1mean: 0.043255
g2mean: 0.034956
bmean: 0.043259
These are internal rawproc 0.0 -1.0 numbers; multiply by 65536 to get the integer number read from the raw file.
On the black side, Libraw reports a black value of 2047, or 0.031234741 in rawproc terms, and the channel mins are a bit below that.
In rawproc, I recently included a mode to set the white point to the actual data maximum from all channels, and an option to set it at the minimum of the channel maximums to obliterate the whitebalance shifting, or as I’ll call it “highlight de-construction”…