Be decent to people. Argue about code, not about the person writing it. Assume the other party is trying to build something good, and ask before you conclude otherwise.
Harassment, insults, and personal or political attacks. Sexualised language or imagery. Publishing anyone's private information. Sustained disruption of discussion. Anything you would not say to a colleague standing next to you.
This applies in issues, pull requests, commit messages and anywhere else the project is discussed, including when you are representing the project elsewhere.
Report a problem through GitHub's private vulnerability reporting on this repository — it is the private channel this project has. Reports stay between you and the maintainer.
Responses run from a private word, through editing or removing the content, to blocking the account, depending on what happened and whether it kept happening.
The substance follows the Contributor Covenant, version 2.1, condensed for a project of this size.