From your very first post it was all obvious. You do not know what you are talking about.
XYZ refers to the color matching functions.
XYZ refers to the tristimulus values.
The button text in the calculator refer to names of the color spaces.
Joofa simply called his [1,1,1] values XYZ, leaving the question open as it being xyz or
XYZ.
CIE XYZ white is specified in xyz.
And no matter how you (properly) slice it, Adobe RGB is fully contained within Pro Photo. Anyone who thinks it isn't is the one who doesn't know what he's talking about.