Orient3d: Clarification needed on behavior of Y axis

[HansBrende]

The README says:

All the functions in this library assume y axis is oriented downwards ↓, so the semantics are different

However when I looked at the code for orient3d, it seems completely identical to Shewchuk's original code (no negations etc. as seen in orient2d)... does this mean the Y axis is right-side up again or am I missing something?

(As far as I'm concerned, the closer to replicating the exact semantics of the original code, the better... so I have no concerns about the Y axis being in the correct orientation, as it makes porting code way easier without having to negate everything. Just want to make sure that's the case... and if so the documentation might need a clarification.)