It looks like big chunks of REBL are being pulled into Clojure core:

>Fogus has been mostly focusing on some new tooling derived from REBL and we are hopefully nearing a point of release on that and some additional supporting libs soon as well.

From third paragraph here: https://clojure.org/news/2023/03/27/deref

This is important because the core Clojure license is true open source vs REBL which had a semi closed license, so it’s always been a little difficult of a choice for many people.