In the case of the explicit app assignment: If you detach an app from a device, this app will be uninstalled on the device. Exception: IGEL OS Base System app is non-uninstallable.
In the case of the implicit app assignment: If you detach a profile from a device, the app configured via this profile will be uninstalled on the device.
For more information on implicit and explicit app assignment, see How to Assign Apps to IGEL OS Devices via the UMS Web App.