[R] grDevices::convertColor XYZ space is it really xyY?

[Bryan Hanson]

grDevices::convertColor has arguments 'from' and 'to' which can take on value 'XYZ'.  Can someone confirm that 'XYZ' is the same as the CIE chromaticity coordinates that are also sometimes refered to as 'xyY' in the literature?  Or are these the CIE tristimulus values?  It looks to me like the first case is true, but I would appreciate hearing from one of the people in the know.  Thanks, Bryan