That's good advice, even just an architectural diagram with notes on each component. It isn't just for public projects though, all projects have new developers coming in from time to time and the easier it is to present the project in a clear way, the less time you'll end up having to spend onboarding someone.

.....although I can be as sloppy as the next person at keeping documentation up to date which is why I think even a high level design and notes is better than nothing.