If you look at the commits in the repo by going to https://github.com/RsyncProject/rsync/commits/master/ you'll see that most of the new commits are tests (click 'Next' to see slightly older commits, the first page doesn't really demonstrate my claim very strongly).
He's mostly using a LLM to increase test coverage, not to add production code.
As LLM usage goes, this is pretty low on the toxicity scale.