There’s a big difference between AI generated code that the human understands completely, the human understands mostly, or the human understands not at all.

"Human understanding" is not yet an objectively quantifiable metric that can be applied to code change sets. As it would only ever be self-reported (a claim made by a user submitting to a repo), I see little to no value in it.

It is quite quantifiable in fact, but I just worry people won’t take the time to quantify it.

I do this exercise myself for code that I really care about: after AI has written the code and I think I have achieved a full understanding, I unapply the entire patch and make sure I can reproduce the patch with the same underlying idea perhaps with less verbosity in the comments. That’s what I call fully understood. If I “mostly understand” some AI code, it means during the reproduction I need to occasionally look back at the AI code to continue.