Huh, this was mostly written 3 years ago at the time of season 1: https://github.com/Lumon-Industries/Macrodata-Refinement/com...
Looks like it's not an official thing, it's a fan project: https://twitter.com/shiffman/status/1512075150857965574 - here's the YouTube video (2h52m from a livestream) where Daniel Shiffman introduces it, at about 34m in https://www.youtube.com/watch?v=7Vmcm25cSTU - then talks through how it works.
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