In this HoneyPot documentary on React there is a nice moment where Lee Byron explains how trying to understand and document the code helped with increasing the quality of it.
There were a couple of problems that I faced right away when trying to understand the code base and build something. (…) the whole bid here was that this would be simpler, but I can’t help but feel like this is really complicated. (…) I wanted to build a glossary. (…) I’d go back to other people working on it, and ask questions like did I get this right? (…) I’d be honing these definitions and along the way we’d realize like, oh this concept and that concept are the same, we’re going to name them one thing instead of two things. (…) Jordan [Walke, original creator of React, ed.] was like “ah this is amazing, this really clarifies the ideas”. (…) That was I think the first shift from this being a thing that existed mostly in Jordan’s head, that other people were playing with, to a thing that all of a sudden felt owned by the whole team.
Highly recommended to do when working with complex systems; create a glossary and get agreement on the terms and how they interrelate.