In the ArcGIS Pro Symbology Pane, the values for different symbol classes are sometimes too long to fit in the cell. Typically in this situation software will provide a tip that comes up when you hover on the value, allowing to you see the entire text string. ArcGIS Pro doesn't do this, and I wish it would.
The attached screenshot shows longer symbol class values that don't have a hover-enabled tip to expose the entire text string.