Context for this question: I am writing an article on MathOverflow for the Notices of the AMS. One thing I try to address is the apparent gender skew of our website. One of the readers of my draft asked what procedures MathOverflow has in place to address harassment or similar misbehavior. Since I'm not a mod, I don't know, so I figured I'd ask over here.
Unless there is an objection, I'll probably cite the answer to this in my article.
My apologies for being slow to respond, but I felt there should also be a response from the moderators here. MO is covered by Stack Exchange's Conduct Policy (https://meta.stackexchange.com/conduct) and has no other separate conduct policy. This policy specifically bans harassment, and empowers moderators to impose penalties, up to banning users, in response to such behavior. The moderators support this policy, and endeavor to enforce to the best of their ability.
At least from the user side, there is a procedure that hasn't been listed yet: following the link to https://mathoverflow.net/contact and contacting support with "I want to report a Code of Conduct violation". This is, as far as I can tell, the procedure most clearly dedicated to preventing harassment.
I don't know how these "contacts" are handled on the moderation side, and would appreciate elaboration from someone who does.