As Opal Kelly Support has indicated, this XEM3001 Custom Adapter PCB is used internally as a Waveform and Timing Generator (WTG). I am not sure if we could sell you a XEM3001 Custom Adapter PCB, and the FPGA firmware and PC software is another issue. The only API I made is for a specific instrument where the WTG is used. I did make a general purpose application (not an API) using Opal Kelly's API directly. If I could sell XEM3001 Custom Adapter PCB then the general purpose application could be included. I would also want to have a general purpose API available if this were something we could sell.
Without providing any software, you would need the XEM3001 Custom Adapter PCB schematic and you would have to write your own FPGA code and PC software using Opal Kelly API.
I think it is unlikely that any FPGA code or PC code would be made available, just compiled user application installer and compiled API.