Hidden apps are apps that are not directly accessible to the user from the Launcher home screen, but can be invoked by another application. When a user selects a link inside a main app, if the app needed for that content has not been whitelisted they will see an error message. For example, if you have an app configured in the Launcher profile that has a web link that will direct users to the browser, you have to whitelist the browser as a hidden app. The browser will not show up in the Launcher profile on the device but will direct users specifically to the content needed. You can view App Attributes for Hidden Apps but the details cannot be edited.