2005 Chevy Cobalt trunk how to get in with dead battery?

You can't get into a 2005 Chevy Cobalt trunk with a dead battery using the standard trunk release button inside the car because that button is electrically operated. The only way to access the trunk with a completely dead battery is to get into the car some other way (spare key, locksmith, etc.) and then access the trunk release mechanism from the inside of the car. There's no external mechanical release on that model.