Porsche 996s have electronically-locked trunks. If the battery dies, you can't open the trunk. To jump start the battery, you must open the trunk. See the catch-22 here?
Thankfully, there is a way around this wonderful exhibition of superior German automotive design.
The whole process is detailed on the real estate blog of Denver's Perry and Co. You should see the whole thing right here for the accompanying photographs, but I'll put in the important details here.
Basically, you open the door with your key, then open up the fuse box in the driver's side footwell. Then you hook up your jumper cables right to the fuse box and the door lock. This will set off the alarm. It also lets you open up the engine cover and that lets you get access to two terminals for jump starting the car, even thought the battery is in the front trunk. Jump start the car, and then you're good to go.
Sometimes, I just love, love, love Porsche engineers.
(Hat tip to the excellent r/justrolledintotheshop and arcsine!)
Photo Credit: Porsche