A manifest is a report that combines data for all the shapes into a smaller number of rows.
This is really useful for office plans or exhibit hall designs to count the number of items like chairs, desks, computers, types of booths, and so on. You can also generate a list of all the components used in a network diagram.
First, make sure you're in data mode by clicking on the Data icon in the Left Bar. Next, click on Actions and choose Generate Manifest.
You can choose which items and what data to include in your manifest by clicking on the check-boxes on the list presented. You'll see a preview of your data to the right.
Once you're happy with your selection, you can choose to Copy to Clipboard, Create Table (this will be inserted into your document), or Save to File, which will export the information as a CSV file.