If a mini-app has come to the end of its natural lifecycle, or further work is required before it is published for consumption by the rest of your team, you can remove it from the list of published apps.
To do so, first make sure that you have selected the 'Show: All mini-apps' option in the main mini-app gallery. From here you can now click on any of the available mini-apps and select the 'Unpublish' button to remove it from the default view of mini-apps, or permanently remove it by clicking 'Delete mini-app' in the right-hand sidebar.