I keep a gallon of distilled water in the trunk. A Rag and that's it really.
Not "Porsche' but emergency related anyway; the frunk has a 42 pcs trauma kit (FirstAid, resuscitation kit, whatever you call those!). Stop bleedings, temporarily patch-up humans, what else it does lol Standard emergency equipment and knowledge for all my vehicles carrying love ones (touching wood now I tell ya).
Also have a roll of cheap grade duct tape. Multifunction but mainly used for those who want to play brave, walk or cycle in front of my car while I'm in motion. I certainly don't want one of these chap to bleed all over my carpet in case I have to take one to the hospital myself one day LOL