I’ve actually been working on a similar thing for the SNW uniforms by printing direct to fabric. First tried TPU, but it’s hard to get a consistent pattern of some of the fine details. Some of them come out better than others. Then tried a transparent PLA–the emblems are small enough that the flexibleness of TPU shouldn’t be necessary–but it didn’t stick very well.
So they’re either using a very carefully calibrated 3d printer (and this is the first time I’ve worked with TPU), or it’s a different technique entirely, like a mask.