The repository contains various projects that we can do using famous microcontrollers, mostly using ESP32 but have done some examples with ESP8266.
As the repository's name suggests, the examples allow us to "talk" with the microcontrollers, using an Android app, and do many interesting things, from which we can learn a lot. I have made a playlist on YouTube, with my videos, which is good first to see them, and then use the repository to help to speed up the process of making the projects, link to the playlist: https://bit.ly/34qoYDY