Also as other people have noted (most notably Fred Brooks and Linus Torvalds), having comments (or documentation) about architecture and data structures is also very helpful.

And literate programming. Well done by Knuth, done by a few other people, but a joy to read when done well.

I think literate programming comes from a time where programming languages where not as high level as nowadays. I don't think there is really any benefit left, and the drawback is the much higher costs of making changes and refactor code, because now you have to move around and keep in sync both code and extensive documentation/explanation.

I think you have to have a more stable goal of the software for literate to work well. But I think most software can be more stable than folks think it is.

Don't get me wrong, some parts of code can easily go through a lot of churn. Hopefully, they would have been confined to a single chapter of a literate attempt. Same as they were hopefully confined to a module or package of a project.

More correct documentation is better. When reading code I'm unfamiliar with, the comments are the only thing I can be certain was never tested.

No, we can't agree. I find the noise of useless comments or documentation can make it much harder to understand a codebase. Sometimes less is more.