That project is a weather station (getting data from openweathermap.org) displayed on an e-ink screen. Code is on https://github.com/paulgreg/esp32-weather-station. The idea is to fetch data then sleep for some time before updating again data. E-ink screen keep information even if esp32 is on deep sleep.
Optionally, it can also fetch local temperature from an Oregon Scientific sensor using an RF module 433Mhz connected to PIN 5 (and 3.3V + GND). Thanks to wonderful ErriezOregonTHN128 library ! https://github.com/Erriez/ErriezOregonTHN128