See the post here for an explanation of the code.

Each .ino sketch is meant to be uploaded on a different microprocessor:

• Arduino: basic morse code conversion for Arduino without wifi;
• Wifi version: version of the morse code for an ESP32 DEVKIT, uses wifi to fetch the message from a remote server;
• Server code: code to be run on a ESP32 DEVKIT, it stores a message and provide APIs to fetch/upload the message from remote. To be used along with the wifi version.