I agree with Zaxo++ that it sounds like it's a convenience sub defined in one of your packages. I'd suggest you try to look it up, then look at what's inside to see how it works. My guess is that where you'll find it is the cornerstone of the system's design; in which case you're probably well off to spend some time reading there and as Zaxo said, to start documenting as you go.

Incidentally, I have to say what you explain sounds like someone spent time to lay down a clean and concise design; kudos to whoever was your predecessor. I would advise you try to understand it all as much as possible and follow the spirit; lest maintenance work turns into a big ball of mud. Good luck :-)