https://help.github.com/articles/deleting-your-user-account/
I've seen this 'ghost user' around on threads for years....
I.e. whether the argument that you're exempt from deleting data under the GDPR just because it's inconvenient for your storage format is going to fly in the EU. If not there's scary times ahead for Git.
Here's a good example of a 4 year old using (presumably) her full name committing to the kernel: https://github.com/torvalds/linux/commit/690b0543a813b0ecfc5...
If that kid grows up, moves to the EU, and wants Microsoft (GitHub) to stop publishing that content, will they be able to just say "no"?
How about if the kid has had their personal data embedded in the Bitcoin blockchain?
Interesting times indeed.