For me, the use-case of commit messages is to help a human discover when some kind of thing might have changed, as distinct from the commits before and after it

For me, the use-case of commit messages is to help a human discover when some kind of thing might have changed, as distinct from the commits before and after it. Importantly, the human is doing a subjective scan for something that sounds relevant. If they already knew what function or detail is involved, they would be already be doing a "all commits that touched this line" filter, and my comment about affecting $thing would probably be superfluous. I also don't need to tell them such details in the commit, because that is better expressed by the actual diff. So in a sense, I'm trying to provide good keywords, about transactions, errors, logging, button color, whatever.