A bundle is a collection of reusable assets. You can migrate assets that use bundled assets.
A bundle can be copy-only, reference-only, or allow both copy and reference. Copyable bundles contain assets that you can copy and modify for your projects. When you export an asset that uses a copy of an asset from a copyable bundle, the bundle does not need to exist in the target organization.
Reference-only bundles contain assets that you cannot modify, but you can reference the assets in your projects. When you export an asset that references an asset in a bundle, both the source organization and the target organization must include the installed bundle.
For example, in the source organization, you create a mapping task that references a mapping that is in a reference-only bundle. You include the mapping task in an export file and then try to import the mapping task in the target organization. If the bundle exists in the target organization, the import is successful. If the bundle does not exist in the target organization, the import fails.