The Wire mobile app has an architectural layer that we call sync engine. It is the client-side layer that processes all the data that is displayed in the mobile app. It handles network communication and authentication with the backend, push notifications, local caching of data, client-side business logic, signaling with the audio-video libraries, encryption and decryption (using encryption libraries from a lower level) and other bits and pieces. The user interface layer of the mobile app is built on top of the sync engine, which provides the data to display to the UI. ...