Damus, Amethyst, Coracle create the 1984 events with their report/block buttons. 

Primal has their own internal table where they store reports and is not creating the events as far as I can tell.

What's more vague, is where they are used. Nostrudel displays them, Amethyst uses them apparently as well. Maybe some relays as well for spam? 

 Primal supports 1984 events on Android on both notes and users. On other platforms I'm not sure what is the status of implementation.