[css-color-4] The CSS GMA, not _this_ See w3c#7610

Author: svgeesus

css-color-4/Overview.bs

@@ -4939,12 +4939,15 @@ Deviations from Perceptual Uniformity: Hue Curvature</h4>
 <h3 id="css-gamut-mapping" algorithm="to CSS gamut map">
 CSS Gamut Mapping to an RGB Destination</h3>
 
-	This <dfn export>CSS gamut mapping algorithm</dfn>
+	The <dfn export>CSS gamut mapping algorithm</dfn>
 	applies to individual,
 	Standard Dynamic Range (SDR) CSS colors
 	which are out of gamut
 	of an RGB display
 	and thus require to be <dfn export>css gamut mapped</dfn>.
+	It also applies to colors being converted
+	to HSL or HWB, which cannot express
+	colors outside the sRGB gamut.
 	It implements a relative colorimetric intent,
 	and colors inside the destination gamut are unchanged.