Copper extracts a lot of infos about your signals and displays them so you can quickly make sure that all parts are connected. Checking all signals is a very important step in getting a PCB assembled, as it's better to find any errors before getting a PCB manufactured.
If you tap on the info icon in the components browser as described here, you will be presented with a view similar to this one:
Find the parts connected to the signal
In the connected parts section of the info screen is a list with all parts that are connected to this signal. You'll see the part name, its value, package name and the pad id that is assigned to this signal. Especially when programming a microcontroller this info is very good as you can quickly make sure the parts are connected at the correct pin ids.
Tap on the info icon to see more details about this part.