Quest'n'Click is a small project with one maintainer. Everyone who opens an issue, a pull request or a discussion is expected to be respectful: no harassment, no insults, no discrimination, no publishing of someone else's private information. Disagreement is welcome when it is about the code, the content or the decision, and stays polite.
Report a breach privately through the repository's private report form: the Security tab, "Report a vulnerability" (https://github.com/Quest-n-Click/quest-n-click/security/advisories/new). It is meant for vulnerabilities, but only the maintainer sees what you write there, so it takes a conduct report too: say in its title that it is one. Any GitHub account can use it; there is no report email address. If the form is not offered, open an issue that says only "I need a private channel for a conduct report", with no detail: the maintainer opens a private advisory and adds you to it. Reports are read, answered, and kept private. A first breach gets a warning; a repeated or serious one gets a ban from the project's spaces. The maintainer's own conduct is held to the same rule: tell them.
This is a short, specific version of the Contributor Covenant 2.1 idea, written for a project this size.