Used to sample a pixel's color from the image preview.
To use the sample tool, LMB anywhere in the Image Preview. Information about the pixel under the mouse cursor appears in an overlay at the bottom of the editor.
In the order of appearance, the following information is shown:
The X and Y coordinates of the clicked pixel. Remember that the left bottom corner is location (0, 0).
The values for the Red, Green, and Blue component as from the Color Picker.
The Alpha value of the pixel.
The Color Managed values of the Red, Green, and Blue component (the color as you see in the Preview).
The Hue, Saturation, Value, and Luminance equivalent values of the Color Managed values.