What are the functions of the side buttons in the Xiaomi Dual-mode Wireless Mouse 2?

The side buttons are Forward Button and Backward Button.
The functions of the side buttons are as follows:
1. Windows system:
Browser: Pressing the backward button will return to the previous page, while pressing the forward button will move forward to the next page.
File explorer: When browsing a folder, pressing the backward button will return to the previously opened folder, while pressing the forward button will advance to the next folder;
2. macOS system:
The macOS system does not support the side buttons function.