Users who collaborate on the same GitHub repo can write on each other's timeline.
This includes github-spray-type writing to inject messages on the user's "pixelated" activity overview for any period.
This is effective:
- even when writes to the repo happened before the victim was a collaborator
- even when the commits predate the user joining GitHub
- when commits are pushed to the repo's default branch
- even when the default branch history is rewritten at any point to include commits attributed to the victim