Sadly there are people who would use a tool like this to make decisions like what to pay their employees. I guessed based on the title that you might fall into that camp. Glad to hear I was wrong.

I could imagine search with some standards (commit message format, branch/rebase strategies, requiring an associated tickets) would be really effective, though not so much the general case. Hope you can share in a follow up post if you find ways to deal work around these problems.