The Umbrella app by Daniël Peppelenbos is a simple Android application that displays JSON-structures downloaded from a website. The app is designed to make it easier to view websites on mobile devices, especially on phones or tablets. Users can create a special version of a website that is optimized for display in the app.

To use the Umbrella app, users need to enter the URL of the website they want to view in the app. The app will then download the JSON-structure from the website and display it in a simple format. The app is free to use and is available on the Google Play Store.

The Umbrella app is a useful tool for anyone who needs to view websites on mobile devices but finds it difficult to navigate them. It is easy to use and provides a simple way to view website content on an Android device. However, it may not be suitable for users who need more advanced features or functionality.