You've reached the installer page of the Squeezelite-ESP32 project, where you can initialize new devices.

Plug the device to your computer using a usb cable or, as needed, a USB to serial adapter, select the hardware platform that matches your device, the version you wish to use and click on the connect button. Note that the I2S-4MFlash platform is the generic version that will work for most devices.

By default, the connect button allows setting up wifi credentials for devices already flashed with support for improv-wifi-serial

It is highly recommended to use the 16 bits versions. See the readme for more details

Not Allowed
Flashing is only supported from the local host or from a secure web site.

Any ESP32 device with a WROVER processor is supported. All that is needed is an I2S digital to analog converter (DAC). There are many writeups on the web that explain how to build one for cheap, or if you prefer, you can also find some pre-assembled options for example here and here

These little gems are the brainchilds of a principal contributor to the squeezelite-esp32 project, who orders batches from time to time and sells them at cost via the Logitech Forums. The hardware design is open source and you can find the project page here with all the details

From the creators: "The first Open software Bluetooth speaker and much more".