This is an ACME client for ESP (ESP32, etc) devices, so your IoT can fetch their own certificate for secure communication. ACME is a protocol (see RFC8555) for automatic certificate management. Sites such as letsencrypt.org allow you to obtain free (no charge) certificates in an automated way using the ACME protocol.
ESP32 espressif IoT development framework (esp-idf) compatible component for Sensirion SHT40, SHT41, SHT43, SHT45 temperature and humidity I2C sensors.