Is there a targeted adjustment feature in the curves settings of GIMP. To set colour curves. Like in Photoshop?
The curves tool in GIMP does not have any adjustment droppers (see the screenshot). However, the levels tool does.
You can make rough adjustments with the levels tool and switch over to the curves tool by clicking the button labeled "Edit these Settings as Curves".
If you click on the image, a vertical line will appear in the curves dialog to show the corresponding portion of the curve.