Incase it doesn't show up:
Yep, sadly I've been exposed to a few such codebases before. I certainly learned a lot about how NOT to design a project.
You've been at it longer than I have, but I've already had coworkers look at me like I'm a wizard for decoding their error message. You do get a feel for where the important parts of the error actually are over time. So much scrolling though...