I guess I’ve worked in a lot of ancient legacy systems that develop over multiple decades - there’s always haunted forests and swaths of arcane or forgotten knowledge. One time I inherited a kubernetes cluster in an account no one knew how to access and when finally hacking into it discovered troves of crypto mining malware shit. It had been serving prod traffic quietly untouched for years. This kind of thing is crazy common, I find disentangling these types of projects to be fun, personally, depending on how much agency I have. But I’m not really a software developer.