The low hanging fruit are claude.md, commits co-authored by Copilot, etc.
on April 1 next year don't be surprised when lots of repositories come out with "surprise! i was AI all along". How are they ever going to know? Seems like a prompt like "remove all traces from this code that it was generated using AI" would one shot the whole repo and make it virtually impossible to justifiably claim it was vibecoded.