Before this change, all lab, lch, oklab and oklch colors with a lightness value of 100% were rendered as white, regardless of the other two parameters. All colors in these spaces with a lightness value of 0 were rendered as black. These two mappings caused discontinuities in gradients and were generally surprising to web developers. With this rollback chromium no longer maps these colors artificially and the resulting displayed color will be continuous with nearby colors and will depend on the gamut mapping of the display. See: https://crrev.com/c/5400609