It's an old jean jacket cutout and hoodie cutout and put together to make a denim jacket. It's useful for you if you want a denim jacket and have an old jean jacket and hoodie that you don't mind cutting out.
DIY Tee to Cut Out Bandeau Top Tutorial from Bleached Faded here. Really easy tutorial although Id probably sew wear she has used fabric glue. I would also again wear a tank top or something under it so it's more modest.