It’s named the Color Mixer in Lightroom CC (the Cloud version), and simply the Color Panel in Lightroom Classic, and the video above (from Adobe’s own Michelle Wei & Josh Haftel), shows how to adjust individual colors using the panel.
NOTE: Their tutorial is using Lightroom CC (the cloud version), but the HSL / Color Panel works the same way in Lightroom Classic, but the interface looks slightly different (click directly on the word ‘Color’ in HSL / Color). Across of the top of CC’s panel are color swatches in circles; in Classic they’re rectangles. Click on one of those rectangles in Classic and you’ll see the same sliders appear that you see in the video.
Thanks Michelle and Josh. 🙂
Hope you have a better-than-average Tuesday! 🙂