Signs of a company that grew way too fast and was very mismanaged. There's absolutely no excuse for a subsystem to be floating around without knowledge of its importance, sadly this is common. It's even more inexcusable that a platform like Twitter would have significant subsystems. I've seen systems 10 times the complexity with less loose ends. Sadly, this is common as well.

It's what happens at most companies. Nobody knows exactly how everything works. Once a system is stable, everyone just slowly backs away, and key development was likely handled by contractors.

It makes very simple issues like this hard to mitigate. Should have done a code review before spending 44 billion. Lol.