I remember seeing information about certified vendors on the website. Could I use a business directory website to find their contact details?
BH8AVW The "tr" feature is an improved design by DL2MAN and PE1NNZ. The website only provides schematics and Gerber files; the firmware is not open-source, but a pre-compiled binary firmware is provided for free. You need to first flash with the serial number to generate the firmware, and then use the displayed serial number and call sign together to download the firmware specifically designed for this machine.
However, due to its continuous active updates and expanded functionality, it offers more features than a standard USDX, such as enabling FT8-like operations with just a USB cable.