This guy (Neil Fraser) wrote https://github.com/lqc/google-diff-match-patch https://github.com/lqc/google-diff-match-patch right before joining Google, which is

This guy (Neil Fraser) wrote https://github.com/lqc/google-diff-match-patch https://github.com/lqc/google-diff-match-patch right before joining Google, which is an incredibly useful foundational library for realtime synchronized text editing. He was very influential in open source work on realtime sync until going to work at Google, when he just sort of disappeared.