> Is there possibility to extend section on XYZ colorspace, explaining it comes from experiments on how  human eye receptors receive color (they obviously do not use technological rgb notation), because it was such source of confusion to me? Also, saying primaries are most possible colored points (greenest green in G direction, reddest red in R direction, etc) in choosen colorspace might be useful , at least I found those remarks clarifying illustrations nicely.
> Example of colormatrix settings also might be useful.
Revision 2, after Andrew's suggestions. Talking about human vision and
colormatrix settings are beyond my skill set and also too much for an
introduction. I have put up a link that may be of interest.
https://peteroupc.github.io/colorgen.html