How to do reporting with the browser-policy package?

I’m trying to implement content security policy via the browser-policy package. But I can’t find any info anywhere on how to do reporting with it. How do I set “report-only” and “report-uri” with it? I want to just monitor violations for some time, before actually enforcing restrictions, to make sure I haven’t overlooked anything. Am I missing something or is that not possible? If it’s not, then how do I go about setting those? With kadira:dochead?