Users can report a listing if they find it inappropriate. All the reported listings are listed in one place in your Admin Panel. To see them, make you pointer click on the Listings icon in your Admin Panel (the 2nd from the top) and click Reported listings.
You will now be able to see all the reported listings. Alongside the listing's title, you will see the listing's author, the creation date, the expiration date etc.
In the example above, the listing created by user Jacek was reported with a reason Misclassified once.
After hovering your pointer over a certain listing, you can choose to clear the reports for this listing (delete the report, not the auction itself), edit the listing (see How to manage listings on website? to learn how to do that) or delete it.
You may also choose to perform a certain action on multiple listings at the same time. To do that, click on the checkboxes to the left of all the listings you would like to apply the action to, select the action from the Bulk actions dropdown menu and click Apply.