Using the reserved register is legal or not?

Hello, all
I downloaded the MCU programm, in the main.c, There is a section listed in the following.
const uint16_t proxyRegAddr = 0x002D;
const uint16_t proxyWrValue = 0x020C;
const uint16_t proxyRdValue = 0x040B;

uint8_t ProxyWrite()
uint16_t addr;
uint16_t wrValue;
addr = SPI_read(proxyRegAddr);
wrValue = SPI_read(proxyWrValue);
SPI_write_slow(addr, wrValue);
return MCU_IDLE;
About the address 0x002D , the explanation in the LMS7002M_Programming_and_Calibration_Guide_v31r05(1).pdf document just like this

It seems that the 0x002D register is reserved. Could you pls be kind to explain it for me ?
Thanks !

@ Zack @ ricardas

The register is reserved, meaning it is a existing physical register that can be written and read. Currently it has no assigned controls or meaning (but exists for future use in case some controls would be assigned to it).
As that chip register is not doing anything at the moment, MCU code just uses it as a temporary data storage.