ESP8266 version 13 DIP switch

Hi, I bought a kit that uses an ESP8266 Arduino expansion board (shield) that has a version 13 ESP8266 module on it. That expansion board is not a standard ESP8266 board.

It has an unusual 2-pole DIP switch on it that can be set to "ON" or "1-2". I need to understand what the 2-pole DP switch does and I need to understand the electrical connections it is connected to.

There are many instructables about the standard ESP8266, but I cannot find any details about that DIP switch in a version 13 ESP8266 arduino expansion board.

Can you please tell me where the DIP switch connects to and why it is needed.
Thank you