As a producer of the mvp, a lot of times there is 'exploratory code' where you're not actually sure how it will work yet; or scale. So you bang out a few approaches and pick the best one for the constraints you have. And basically never touch it again.
In one case, I was working on the mvp and the team who would be maintaining it where the one's doing code review. The code turned out way better than either of us would have come up alone. It ended up being one of the coolest projects in the company and some internal secret-sauce for making money. For example, I remember one code review where they asked to add a configurable callback in. I was like 'why?' and they answered, "we're already being asked if it can do X, if you add a callback here, here and here, we can already start building that feature so you can focus on the core."
