This quest to discover XEP-0408 (Mediated Information eXchange (MIX): Co-existence with MUC) was automagically added, to fulfill the quest at Discover XEPs. As of 2018-05-21 the status of this Standards Track XEP is Experimental. What does that even mean?! Check it out at XEP-0408: Mediated Information eXchange (MIX): Co-existence with MUC 