This is an official BMW photo of its all-new G450 Enduro machine that has been competing (under stealth) recently in off-road events. Below you will see a close up of the off-set rear suspension (which allows a straighter intake) and compact 450cc motor (that is canted forward several degrees more than most competitor's singles). The unusual drive shaft integration with the swingarm pivot cannot be seen in this photo because it is located on the opposite side of the bike.
I am guessing the countershaft is what they are talking about, not a shaft drive. It clearly says pivot - not the whole swingarm. I am assuming this was done to keep chain slack to a minimum while the bike is bouncing.