Neat tool, Jaakko! Reminds me a lot of the book "Your Code as a Crime Scene" - we could definitely benefit from more tooling in this area!
By the way, I noticed your authors chart has a number of duplicate/near-duplicate entries (ex. "Anna Buianova" and "Anna Buyanova", "Arun Kumar" appears twice) - are you familiar with git's mailmap feature? It's really useful in situations like this for canonicalizing author names!
Oops, it seems I forgot to recommend having a mailmap file. :-) So thanks for mentioning it.
For statistics like this, I have always written a mailmap file and kept it up to date, since as you say, it's very useful to have canonical author names and to have git always use the same name. For this post, though, I picked the dev.to repository since it's code that is common to everyone here, but it doesn't have a mailmap file, and I didn't want to do too much polishing just for these sample graphs.
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