What is the purpose of the lever located in the center console on my 2014 XJ Supercharged?

 

That's so you can get the car out of gear in case the shift knob is broken or won't rise up. Very handy to know about!!
Otherwise the transmission has the rear wheels locked so the car is very difficult to move.

Oh I forgot you need to pull the red strap up to activate it.
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Here is a video explaining it.