What are the extra linkages at the front suspension for?
this is something really interesting .. will have to look out and see how much they have developed the front suspension.
The supposedly extra linkage is the steering arm which is not anymore positioned ahead of the front upper wishbone. Honda also had this in 2006.
I think McLaren have found it necessary to de-couple them because they have moved the wishbones themselves more to the back. If you'd look from the top, you will see that the wishbones do not connect to the wheel on its vertical centre line, but more in the back. Either this position is correct for in the upright, or McLaren have designed a front suspension where the wheels do not turn around their axis - which is a very interesting, though weird thought.
Anyway, because of that position and because of the limitation of surface of suspension components seen from above, McLaren probably had no other choice than de-couple them, providing the extra advantages that the steering system could be positioned lower into the tub.