Pretty sure you’re thinking of tzdb, the time zone database: https://onezero.medium.com/the-largely-untold-story-of-how-one-guy-in-california-keeps-the-worlds-computers-on-the-right-time-a97a5493bf73

An adjacent and thematically resonant story is the volunteer effort that powers curl, which so many people use: https://thenewstack.io/the-world-runs-20-billion-instances-of-curl-wheres-the-support/