This website does not collect or transmit any personal information whatsoever. It implements a web development tool that helps test local files in your browser. The files never leave your device and are not transmitted over a network. This is achieved with the use of Service Workers, which run on your local device, rather than using a traditional server.
If you allow this tool to access files that contain personal information, then the tool will access those files solely to perform its function of allowing you to test those files in your browser. The contents of the files will never leave your device or be shared with anyone else in any way whatsoever.