Add a Notes free text box on the Details tab for each application (or on a separate Notes tab). These notes would be visible to any admins, but not to end users, and could be used to add useful reminders about an app (eg, why particular deployment options have been chosen, anything weird that is specific to that app etc).

Someone might have a reason to add some notes to an application - e.g. reminding themselves how to use it. They could add notes and view them in more information.