It is MLS, just transported differently. It uses coordinators, which are just as dumb, or even dumber than, relays these days, for the ordering of messages (MLS requires strong ordering, which is why Marmot struggles so hard to work properly). Nostr relays transport messages between coordinators and clients using CVM, so everything is ephemeral on relays. It uses Nostr keys for identities, just like Marmot.
Cordn and Marmot are not compatible (though they could be), since MLS is such a complex protocol. Given their different requirements, they would need to agree on certain parts that they currently don’t. Happy to keep clearing doubts any time. The
@Gzuuus article explains this very accurately.