Spectral Locus From 2 Degree Cmfs From cvrl.org/ciexyzpr.htm Desaturated in Oklab With Frequency Increasing Linearly With X

Linear with respect to light frequency rainbow desaturated in an approximately perceptually uniform color space to not clip out of gamut.

What did you not understand?

everything

and that makes sense because do you know how to pronounce a breathy-voiced mid-central vowel

Light is a wave. The colors of the rainbow from red to violet correspond to light of increasing frequency. The picture shows the colors of light with frequency increasing linearly with the x coordinate, except the colors are all brought closer to grayscale in an approximately perceptually uniform way to avoid any colors being too far away from grayscale to show up.