Puzzle sources

I noticed that about half the puzzles in lishogi come from sources outside games, unlike in lichess. In particular, I noticed a lot of them come from yaneuraou.yaneu.com.

Where are the puzzles from yaneuraou sourced from? I couldn't find information on that website (which if I understand is the engine that's used here). Are their puzzles publicly available on their website as well?

You can't post in the forums yet. Play some games!