What should I configure as a front axle when exporting fbx from blender to unreal?

I want to know the fbx export settings from blender to unreal. in some forums it is mentioned that + x is advanced, but when I tried it on my pc, + and it is advanced, because when I align the scene in the front view, + and it is pointing towards my side. but it is suggested for export fbx that we have to establish -x as below, why is that?

What should I configure as a front axle when exporting fbx?