The ArcGIS Pro document titled "Change the symbology of imagery" has some typos. The typos are under section RGB. The following shows the original texts excerpted from the above document. The texts highlighted in red should be 20 to 225.
Minimum Maximum displays the values on a scale from the actual minimum and maximum values. For example, if the dataset is 8-bit but the values range from 20 to 225, the display is stretched from 0 to 255. This increases the ability to see differences in values throughout the dataset.