Yes it contains the MOTs software/firmware. This either reads the music DNA and stores the data as descrete files in the BM5 or forms part of a two-software code (one in the BS5 ,one in the BM5) which allows the BM5 to do the same.
Every track has a file and I guess a code/reference which the BM5 "player" element can rank and order for a MOTs playlist.
If this was not the case, BM5 alone would play MOTs and everyone and his dog would have cloned the saftware onto their music players. This arrangement protects B&O's copy-right.
Effectively the BS5 is a "Dongle" as well as a monitor and keyboard/mouse)