So is there any known current developing going on based on XEP-0280 ?
Probably not. There isn't even a Jira ticket for it.
On top of that it is still in experimental state and there are long-standing issues which are unresolved since many years (like XEP-0079 and XEP-0198)
On the other hand it seems relatively simple to implement. I might even give it a try.