As found by @conhlee and documented in [my BRCAD specification](https://github.com/patataofcourse/flour/blob/master/SPECIFICATION.md#animation-1), the value unknown1 [in brcad.AnimationStep](https://github.com/rhmodding/bread/blob/c3388c63a726cfb24c50542c2d48f7dde8ce71f3/src/main/kotlin/rhmodding/bread/model/brcad/AnimationStep.kt#L11) represents the X and Y offset of the sprite. Would be nice to have support for this added to Bread.