How would you identify "who actually understands a codebase" from git history?
I've been experimenting with git-history analysis and found an interesting problem.
In one project, a directory showed ~65% ownership concentration around a historical contributor who hasn't committed in 2 years.
In another project, a directory showed ~70% ownership concentration around a contributor who committed 4 months ago.
Same concentration number, completely different maintenance story.
It made me realize ownership concentration alone is probably not enough.
If you wanted to estimate "who currently understands this part of the codebase well enough to review and maintain it safely", what signals would you look at?
Commit history?
Review activity?
Churn?
Bug-fix commits?
Something else?