The source code for the UI Recorder tool is available on the WinAppDriver repo here.
The UI Recorder tool aims to provide an intuitive, and simplistic, user interface that is divided into two panels, as seen below:
UI Recorder tracks both keyboard and mouse interactions against an application interface—representing a UI action. When Recording is active, both the top and bottom panels are dynamically updated with varying UI element information every time a new UI action takes place. The Top Panel shows the generated XPath query of the currently selected UI element, and the Bottom Panel shows the raw XML information for the same element. You can navigate to the C# Code tab on the bottom panel to view generated C# code of the recorded action which you can use on a WinAppDriver test.