Are to you talking about the review app? If so, I suggest to contact the App provider directly for this issue
If you're looking to replicate the app block description that is in your screenshot, for your own app, you can add a description that is visible on the theme editor with the `label` value that is accessible within the schema settings of an app block. You can see an example of what that would look like in this sample theme extensions getting started repo here.
Hope this helps!