Big parts of the Fiori Applications for S/4 are build using SAP annotation syntax. SAP Annotation are evaluated during runtime by SAP UI5 libraries which then render the UI (User Interface).
SAP mobile team has added a new capability into the SAP Business Application studio to generate a mobile solution based on an existing web desktop solution. With the wizard-based generator developers can now generate a basic version of a mobile app based on the annotation-based web app.
This has the big advantage that the mobile app now has full access to all mobile features out of the box. Data can be offline, push messages can be received and barcode scanning can be added via drag and drop. And since this code base is completely decoupled form the desktop application all new features on the mobile app hav no effect on the core desktop web UI.
Trying to support a mobile and a desktop app in one code base will lead to a small subset of features and suboptimal runtime experience. With the new generator the developer has now the chance to create a net new app based on the desktop app. this will allow to support and further develop the mobile app much faster and more efficient.
test drive this yourself in less than a half hour: