The Tz database is fascinating, the amount of random data you'll find in there for the sole purpose of calculating time and date is bizarre. The Tz database has an estimate of the Big Bang, there are several time zones that have hundreds of hard coded daylight saving transitions, or manually calculating when ramadan happens and placing that data in tzdb files.
Related, I have written about the formatting of the TZ database and other representations before: https://gitlab.com/libtime/documentation/-/wikis/Timezones
The Tz database is fascinating, the amount of random data you'll find in there for the sole purpose of calculating time and date is bizarre. The Tz database has an estimate of the Big Bang, there are several time zones that have hundreds of hard coded daylight saving transitions, or manually calculating when ramadan happens and placing that data in tzdb files.
https://news.ycombinator.com/item?id=45162559