As time went by, everything started to make sense and I was able to grasp almost everything about the environment and the tech stack. Even perform a little bit of system analysis in COBOL to try and identify some gaps in the code base.
But what always intrigued me is that even those senior developers in the team with 25+ years of experience with COBOL wouldn't ever touch this one program. The program responsible for 90% of the logic of the product of that company. Every now and then, this program would ABEND for whatever reason and sometime, no one could figure out why. They respected (cute way of saying they were afraid) this program so much that, instead of refactoring it, they would just throw an if statement and let it run.
This program was built in the 60s and had I don't know how many hundreds of thousands of lines of code. It is still running to this day.
Now I don't have the expertise to say if that was bad code, and even if I had, I didn't deal with this program enough to say this anyway, but I was very intrigued why would this particular program ABEND out of nowhere, and no of these super experienced developers would have the guts to touch it.