You can use LLMs in multiple ways, from very hands on to make local changes to completely hands-off.
I've seen plenty of code that was LLM generated but the commit message itself did not have the co-author attached to it. This only seems to happen when someone's interface to the codebase is completely though Claude/Codex/..., and those are usually the most verbose commits, and yet they say the least, because they just summarize the code changes, not the why.
On the other hand I've seen developers using Claude as a tool. They have VSCode open and a terminal window with Claude and go back and forth, ensuring they write correct code, and leave the plumbing to Claude.
So maybe the author of the code started off small and it grew over time?
I would expect a mature code base like rsync to have a lot of unit tests and integration tests and frankly if there's not enough that such bugs haven't been caught; that should be your first use of LLMs in order to setup some deterministic guidelines when you do start making changes to your actual code.
I have been experimenting with both aforementioned styles with interesting results.
> I would expect a mature code base like rsync to have a lot of unit tests and integration tests
You might be surprised. C applications which interact heavily with the system - like rsync - can be tricky to test comprehensively, as it's nontrivial to inject faults into system calls. If the application is architected to support this kind of testing, or uses a HAL, that may make matters easier - but an older codebase like rsync probably isn't.
I've seen plenty of code that was LLM generated but the commit message itself did not have the co-author attached to it. This only seems to happen when someone's interface to the codebase is completely though Claude/Codex/..., and those are usually the most verbose commits, and yet they say the least, because they just summarize the code changes, not the why.
On the other hand I've seen developers using Claude as a tool. They have VSCode open and a terminal window with Claude and go back and forth, ensuring they write correct code, and leave the plumbing to Claude.
So maybe the author of the code started off small and it grew over time?