The tone curve is one of the most powerful yet underutilized tool in Lightroom. A large part of this is because it is not easy to learn. But with these interface changes, Adobe can make it much more intuitive.
Color grade in Lightroom like a pro. This chart lets you use the Tone Curve and HSL adjustments in Lightroom with better control and precision. It makes using the tone curve incredibly easy and lets you see exactly what colors you are achieving.