Well, just updated the BenQ monitor software and here's what it's saying (de2000) after running it with an i1 Display Pro (large target, 16 bit LUT profile 6500/2.2/100 )
Minor irritations are that the 'writing to LUT' stage of the software is slow and that I can't use the software with a 2nd monitor, so have to switch to another
Interesting. The pure green is outside ICCLAB's gamut.
The Lab values are adapted to D50 from D65, xyY colors are, of course, correct (white point=D65). The green RGB (0,255,0) is clipped since ICC Lab space is limited to -128 in the a* and b*. The actual pure green CIELab values (adapted for D50) are (83.8, -143.3, 85.1) from Bruce Lindbloom's calculator.
This is an intrinsic limitation of ICCLAB and use of ICC profile LUTs which requires LAB PCS. Matrix profiles do not have that but you can't get as good color accuracy with them. Not an issue with printable colors of course.
Unlike ICC profiles, LUTs that are inside a monitor are not limited to ICCLAB.
That's quite a bit of clipping. Curious as to what unclipped, measured values are.