Maybe we could store metrics about the code in the history as well? This would indeed reduce vendor lock-in. This tool makes it easy. Unsurprisingly seems built upon git notes.

I like the idea of getting all the review comments back into Git once things are merged. This works offline, makes you less dependent on the forge for historical data etc. Now we'd probably need to have the notes feature easier to use somehow.

Aren't we loosing something if we focus on productivity numbers too much? A good reminder that intrinsic motivation is an important driver in people behavior. I wouldn't throw all the metrics out of the door but they'd better be a limited amount and they'd better be informative rather than objectives.