Browsing pull requests, I found this one: https://github.com/macports/macports-ports/pull/305
Another commit had happened to that port in the mean time, so the PR now had conflicts and could not be applied as-is. GitHub invited me to edit the file on the web to resolve the conflict, so I did. I was then asked by the PR author not to do that. Can someone explain why resolving the conflict was bad?