yeah so, I wanted to make something that was functional too, like a usb stick but the only COTS solution was to add an SD card reader, so those footprints are for an SD card using USB-C and the the only microchip serial-to-sd IC I could find. When I add them I will tell you if it works. I also discovered the concept of "oreo" PCBs on hackaday.com which I will probably design in the next few months as it looks really interesting. But it's an awesome instructable mate, keep them coming!!!
Absolutely brilliant - works like a charm, used svgtoeagle on github to generate my own drawings. Added some features but haven't tested yet