This is a gift card holder for "peg hook" style gift cards. They're larger than the standard credit card style and typically sold in supermarkets, drug stores, etc. I, personally, add text to the front for the recipient. I don't know OpenSCAD at all, so here's a link to the Tinkercad project of you want to mess with it.
giftCardHolder-Rounded-Body-Whole.stl | 98.5KB | |
giftCardHolder-Rounded-Body.stl | 49.5KB | |
giftCardHolder-Rounded-Head.stl | 49.1KB |