[BUG] In fbx_output, why does quaternion rotation uses the `@` operator instead of the `*` operator?

[TypeDefinition]

I can't seem to find anything online mentioning an @ operator, and mathutils' documentation states that we multiply using the * operator.

https://docs.blender.org/api/2.79/mathutils.html?highlight=vector#mathutils.Quaternion

I am trying to get the accumulated rotation of the wrist and hands. But using the * operator seems to result in no rotations.

In my code:

In fbx_output.py:

[TypeDefinition]

Just use the @ operator.