I count a minimum of 750 commits or contributions to xz by Jia Tan, who backdoored it.
This includes all 700 commits made after they merged a pull request in Jan 7 2023, at which point they appear to have already had direct push access, which would have also let them push commits with forged authors.
Probably a number of other commits before that point as well.
Distributions are reverting the identified backdoor. This is insufficient given this volume of activity. Revert to before any of this