This tale has overtones of the Van Halen brown-M&Ms story (https://www.npr.org/sections/therecord/2012/02/14/146880432/the-truth-about-van-halen-and-those-brown-m-ms).

We all cut & paste code from time to time. But we need to understand what we're pasting in. If we don't even bother to look it over — such that we leave obvious telltale signs like those comments — then that's a problem.