This module is a very basic implementation of XEP-0377: Spam Reporting.
When someone reports spam or abuse, a line about this is logged and an event is fired so that other modules can act on the report.
With the plugin installer in Prosody 0.12 you can use:
sudo prosodyctl install --server=https://modules.prosody.im/rocks/ mod_spam_reportingFor earlier versions see the documentation for installing 3rd party modules