color-interpolation: sRGB (default) vs linearRGB - the same black-to-white gradient; linearRGB is lighter at the midpoint.
icc-color(): top swatch is the sRGB fallback alone; bottom swatch names a linear-light RGB color-profile (0.5, 0.5, 0.5), so it converts to a lighter gray.
color-interpolation on a mask: the same 50% gray mask over a red bar - sRGB (top) vs linearRGB (bottom, more transparent).