In Scratch 3.0 the order of the arrow keys are: left arrow, right arrow, down arrow, up arrow.
We would expect up arrow to come before down arrow. Or, the ordering in Scratch 2.0, "up arrow, down arrow, left arrow, right arrow." Two reasons for keeping the order as in Scratch 2.0 is that "up" is clearer to kids and also comes first on most keyboards.
Scratch 2.0

Scratch 3.0
