It is this box I guess 

Location: Denmark

I was wondering the same. I assume its a essence or core without any ports.

My question would be why is this a separete box for a product whot this price tag? I know that the BS9000 is probably packed inside, but when it is restored something might be possible to do. Even piggybacking in an enclosute that matches the back of the BS9000 could be an option

If it is a separate box with its own name, then one could expect it will be commercial available! Is it a new intermediate to connect older devices to NL?

I just now realized that the product page says Encore. I just thought it said core when I first read it. Based on the use of the name Encore it could suggest a more basic version as it was the case with the Beosound 5 vs Beosound 5 Encore

It essencially is a small box, that connects a ML product - in this case the BS9000c - to the USB-C port of a Mozart-based product - in this case the BL28’s - (and some sw). It makes it possible to listen to and to control the sources of the 9000c - first of all the CD’s - with the Bang & Olufsen app/remote. There is - apart from the mentioning on the website for the 9000c/28’s combo - little said from B&O about it….you get that in the package. I (and others) would find it very strange, if this box would only be sold as part of the 200 piece 9000c/28 combo. There are several use cases, where this could help integrating old ML Beosounds with e.g. the BS Theatre…….not just with the thousands of BS9000, that are still out there doing their job, but also….. Please note! I have no further knowledge or insight - my thoughts are solely based on how it is described to work with the 9000c on the website. Untill now there is no user guide or alike for it in the Costumer Support section there. My best advice would be to ask a dealer about it and if this will be available generally. This way we could let B&O know that we would like to buy it seperately. I indeed, would like to have one ? MM

Or two?

According to @c-larsen, it is a converter from USB-C to ML interface, for *audio masters* only.  I believe this means you can't push the sound in the other direction to the 9000, nor can you hook the converter up to your BeoVision 10 to get sound or control it.  According to @k-rasmussen, he doesn't believe it can control the BS3200 incl. hard disk.  From these 2 informed comments, I feel that either it only works for the BS9000, or if a broader view of @c-larsen's comment is taken, then at the very least nobody has really tested it with anything else. @k-rsmussen also said that the 9000 works in Option 0 (no ir) and the Beolab 28 or a Beoremote One can control the CD number, track, play pause, also with the MyButtons.  Because ML is used, it's analog output, not digital (not the SPDIF), so the analog input via USB-C pins as configured in the interface spec in the Beolab 28 can therefore receive A.Aux (& presumably AM/FM in the USA) as well as the CD sound.