ESP32, where are TLS connection (WiFiSecure) CA certificate?

[ligantx]

• Arduino board: ESP32

• Arduino IDE version (found in Arduino -> About Arduino menu): 1.8.13

Although I see ESP8266 have a fingerprint in order to connect with TLS credentials, i have search all code and libraries included, but i cannot find CA certificate for ESP32 secured connection to AdafruitIO.
WiFisecure example of ESP32, has CA certificate hardcoded, but in adafruit's example (although it's working fine), there is nowhere a fingerprint or CA cert. So, how the connection is secured?