It's product name is Door Appeture Foam Tape from 3m..
It is mostly used for masking door jambs, around the trunk,gas door , and hood etc..
It comes in a couple sizes and is coated with a adhesive for just a quarter of it's circumference so the curve works to soften how material hits. I marked the adhesive part so it woud show in the pic.
I've found the 1/2 inch to be the best of the sizes to do jambs as well as blends and other tricks/saves.
It can be reused a couple times so save the used stuff in a separate box.
It is great for masking when spot priming so you don't get that hard edge on primer..