PCIe's cxpl_debug_info

In TRM we find PCIE_X_RC_PF0_PORT_LOGIC_PL_DEBUG1_OFF_0 registers with the following description:
Description: This register holds cxpl_debug_info[63:32].
Where do I find description of cxpl_debug_info?
Thanks!

Not all registers are public. If you met specific issue, please share detail info and then we may be able to check the necessary info.