default normal direction for arnold renderer

I know it's not realtime, but maybe someone has this info here. I can't find it elsewhere and the folks at the Autodesk forum aren't much help.
I'm wondering what R/G channel directions Arnold expects by default for normal maps. It comes with two check marks in the node flipping whatever it's expecting to come in by default. I'm not sure if it's saying it's backwards, and flipping the standard (whatever that is). Thanks!

https://forums.autodesk.com/t5/maya-shading-lighting-and/arnold-normal-map-direction/td-p/7391927