Meta Depth API Question

I am trying to understand the accuracy of depth API for quest 3 under different conditions

For that I want to be able to get the distance of the depth hit point from a fixed point let's say the centerEyeAnchor using the MRUK Raycast

My question is where is the centerEyeAnchor placed w.r.t to the physical headset, what I understand is it is the user view so somewhere near the headset lenses, is there a specific number anybody knows or if you can point me to anywhere this offset from the actual physical sensors is mentioned!

Thank You!