Today Facebook open-sourced Tweaks, an application framework that lets iOS developers test changes to an app in real time, simply by using an iDevice, 9to5Mac reported. Incorporating Tweaks into an app provides a new settings menu by which developers can change parameters that affect how the app looks and feels—as it’s running on an iDevice.
Changing such parameters usually requires a developer to “recompile” an app, which can be time-consuming for repeated testing of different combinations. Some of the adjustments developers can make affect animation timings, colors and motion speed.
Facebook says it relied on Tweaks while building Paper, Facebook’s news reader application. You can find Tweaks on Github.