> But do the humans need to actually understand the code? A "yes" means the bottleneck is understanding (code review, code inspection). A "no" means you can go faster, but at some risk.

I always thought of things like code reviews as semi pseudo-science in most cases. I've sat through meetings where developers obviously understand the code that they are reviewing, but where they didn't understand anything about the system as a whole. If your perfect function pulls on 800 external dependencies that you trust. Trust because it's too much of a hazzle to go through them. I'd argue that in this situation you don't understand your code at all. I don't think it matters and I certainly don't think I'm better than anyone else in this regard. I only know how things work when it matters.

If anything, I think AI will increase human understanding without the need to write computer unfriendly code like "Clean Code", "DRY" and so on.