That's very interesting. I'm always impressed at how dedicated some people are to old systems too. My Spectrums haven't been touched in 15 years and here's people making graphics cards for them still.
As I understand, the FPGA is to interface the Z80 with the raspberry pi that's onboard to include extra graphic modes and HDMI output, but I could well be wrong. There's a lot of unanswered questions about its inner workings, but they have some good looking test boards already etched.
