I've Google Translated the readme file in the GitHub repo and it says: > At present, the content farm is flooded, and only sites with good experience are inclu

I've Google Translated the readme file in the GitHub repo and it says: > At present, the content farm is flooded, and only sites with good experience are included in the whitelist. https://github.com/txthinking/soso/ https://github.com/txthinking/soso/ Based on that, my interpretation would be that it's an opinionated search engine that indexes a limited set of sites that it considers to be "good", ignoring everything else.