Oh for sure. Just look at the "Author" page. It says he started in March 2026 on this. Which means last month he pointed Claude to the Notepad++ repo and said "make a native port of this to macOS".
Even if the code was written by author, not bothering to remove co-signed-by part from the commit message (assuming author did indeed wrote it by himself) let alone not writing their own commit message is an indication of negligence to me