Where to find "Diagnostic Status Register"

Hi,
In my continued effort in creating a diagnostics function I am reading abot a “diagnostic status register” which contains information about the local bus master.
This register is explained in detail in the Diagnostics document (Diagnostic registers and error messages, UM EN AXL F SYS DIAG) and on the help site (Diagnostics - Local bus (plcnext.help)).
However, I cannot find any information about how to actually find this information so that I can use it in my program. I can find it in the web based management, but not in any function or global variable.
What have I misunderstood here ?
Here is my diagnostic status register as read from WBM:
image.png
Here from the document:
image.png

Ok, I found them as
AXIO_DIAG_STATUS_REG_HI
AXIO_DIAG_STATUS_REG_LO
image.png