[cerved]

> Honestly, a simple data-driven heatmap showing which parts of the code change most often or correlate with past bugs would probably give reviewers more trustworthy signals.

At first I thought this to but now I doubt that's a good heuristic. That's probably where people would be careful and/or look anyway. If I were to guess, regressions are less likely to occur in "hotspots".

But this is just a hunch. There are tons of well reviewed and bug reported open source projects, would be interesting if someone tested it.