Bundles allow you to refer to a group of objects as a single unit. This is useful in situations such as lighting where you can link a bundle of lights all at once.
You can use a bundle name prefixed with a @ sign (for example,
@lights) to stand for the contents of the bundle in any parameter that
accepts a list of nodes.
Use the bundle list to view and edit bundles. See how to use panes for information on adding a bundle list pane to your layout, or choose Windows > Bundle List to get a bundle list in a floating window.