Be decent. Specifically:
- Discuss the code, not the person writing it.
- Assume the other person is trying to help until they prove otherwise.
- If you are told your tone landed badly, take it at face value and move on. Nobody has to litigate whether the offence was reasonable.
- No harassment, no slurs, no dragging arguments here from somewhere else.
This applies to issues, pull requests, discussions and any other space the project uses.
If something needs dealing with, open an issue or write to the maintainer through the address on their GitHub profile. The maintainer decides what to do, which may include editing or removing comments and blocking accounts. That is one person's judgement, not a tribunal, and it is applied to keep the project usable rather than to settle scores.