The locality is restricted to action or user-transform only. Or as it goes
in the code now: by setting a constraint local, it executes the constraint
before it calculates the influence of Action or user transforms.
ALso note that this works in Evil Eulerians. Meaning that when you only
want to copy the X,Y or Z compenent of a euler, it can give unpredictable
results when the other euler values are set, this because euler axis
rotations work on top of each other.
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