The first row is the object’s X vector, which points to the right of the object.

In a left handed system

In Direct3D period, and indeed row-major matrices period.
Why is there suddenly all this confusion about handedness?
The difference between left-handed and right-handed doesn’t exist until you render something to the screen, in which case the projection matrix is different. Until then, nothing else changes.

Sorry, I maybe should have been more selective in my quote, my previous post outlined my thoughts, but to reiterate, In a RH system, +x would point to the left, if z+ was our forward vector.