Dual-screen web browsing on emulator and device
The dual-screen web enhancements are available in Microsoft Edge version 97 or newer on the Surface Duo emulator or your Surface Duo device.
Testing in the emulator will help you understand how your web app interacts with the on-screen keyboard, for example, which is difficult on the desktop developer tools.
Debug on the emulator from the desktop
In addition to building and testing on Edge desktop, you can also connect to the Surface Duo emulator and debug websites from the emulator.
Follow these instructions to connect an emulator instance to Edge desktop developer tools. Remote debugging also works for Android devices.