I want to revisit the question of having a formal code of conduct (#6070).

I just had a longer discussion with @reshamas, that I think somewhat reflected the points brought up by @willingc in #6070 (comment)

We do clearly have a diversity problem in the project, and at least in the US, the absence of a clear code of conduct might impede our ability to broaden the community.

@reshamas pointed out https://stackoverflow.com/conduct as a positive example.

Having a code of conduct more visible, such as suggested by the NumFocus project website standard might also be useful:
https://github.com/numfocus/doc-standards