My interpretation of this is they pay for API access and sends anonymised queries to Google and/or Bing.

I'm still puzzled how they get so extremely much better results compared to using any of thise directly or using DDG which does the same only with Bing.

Also a bit worried because I think there was a time when DDG felt the same before they suddenly gave in and started serving answers for queries I didn't ask just like Google but I'm not really sure.