In my Table of Contents, I have a layer that is named "symmetrical differences" but I am not certain it was created using that tool.
The geoprocessing history is often included in the metadata of the item, and it is also logged in the geoprocessing results window. More info from ESRI here
I found this on the ESRI website...
Whenever you execute a tool using its dialog box or in the Python window, information about the execution is written as a result in the Results window. You can learn more about the results window from ESRI's help page
Here are a few helpful tips to keep in mind as outline by ESRI.
There are a number of useful things you can do with results in the Results window, such as
Open a previous execution of a tool to change a few parameters without having to reenter all parameters, then rerun. Create a geoprocessing package or geoprocessing service. View the status and messages of a tool executing in the background
Here is a breakdown of the Results window