We've noticed that Extensions and Addons are responsible for CSP reports, and it's hard for us to debug that.
It would be nice if there was a flag in the report that specifies if the violation was initiated by an extension or an addon. I understand there are challenges on doing this (eg, an extension can inject a script which later generates a report). Being able to differentiate this problems would assist us to more quickly and efficiently reproduce and triage bugs. This goes hand in hand with the other request (generating a DOM event/error on CSP violations).
