The file 'Hatchbox Cardboard Stack-up Corner 3D Printer Model' is (stl) file type, size is 12.8KB.
Really liked JHON_DOOM_MAKER's design, and adapted it to fit snugly on hatchbox cardboard packaging. There one wall is triple thickness, and the other is a single, so that required some cut-to-size.
https://youtu.be/UOrY_K12cbU