UGN -- unusable game notation. That has a ring to it.

UGN was designed with SPARK and AWS S3 pbzip2-aware threading JSON readers in mind. For an analysis of a year's worth of lichess games -- over a billion, maybe more -- I believe UGN is a good solution. Try bucketing clock time vs. blunders or castling analysis or opening vs. ELO on 1 billion PGNs. Not simple search; aggregation. In the end, UGN is an information architecture; JSON is used as a convenient implementation/representation but it happens work well with SPARK and S3. And you can reliably use jq or even grep on the same UGN files. I didn't feel the need to create yet another binary format.

Anyhoo.... We're up to 60 downloads!