We have all this commit data at scale, it really feels like there are interesting stories or lessons that could be extracted from them.

There's kind of the obvious operational stuff like: What are the properties of commits that introduce bugs compared to those that don't. Which type of commits are rarely changed and which are more likely to be changed over time. But what I'd find even more interesting is some insight into how we solve problems and how well we're able to solve them. I guess part of the puzzle is missing - the external requirements / environment that give rise to some number of the commits.