The biggest thing was an internal system for medium frequency trading.

It had a lot of moving parts of which agents were the top 30% other systems would interact with. Storing, retrieving and ranking the information was the more important 70% that isn't as glamorous and no one makes courses about.

I still have no idea why everyone is talking about whatever the hottest decoder only model is, encoder only models are a lot more useful for most tasks not directly interfacing with a human.