There seems to be some useful info about this board here:
https://gw4sae.wordpress.com/2017/03...-ssb-receiver/
it looks like someone in that link has reverse engineered the schematic. It also appears that some people are using it as the heart of a homebrew HF receiver because the first mixer, the IF strip and AGC and product detector are all there. Obviously the LO and 9MHz BFO signals are missing but this would be easy to add. I'm not sure how much AGC range it offers but probably enough for casual HF listening on a ham band for example.