If you use some plugins that connect to external APIs in your app, it is very likely these APIs will add some data types to your application. For instance, if you're connecting to Twitter, a type of data that Twitter returns if you make some calls to them is a 'Tweet'. These data types are quite similar to the custom data types defined above, as they can describe things and have some fields. In many places of the Bubble Editor, you will be able to use them similarly to above. For instance, if you're using a repeating group to display a list, you will be able to pick 'Tweet' as type of content. However, the main difference is that you cannot create things of this type (you cannot create a thing of type 'Tweet'), and you cannot modify them.