You can view the history of the backlog. For example, this can help you see which items were added or deleted, or when comparing current requirements with those at the start of the project.
1. Open the Product backlog tab.
2. Click More > Product backlog history > View product backlog history.
3. You can also use the keyboard shortcuts Ctrl+J or Cmd+J).
The Product backlog history window opens. Differences between the historic and current versions are displayed in gray.