Explanation
Mutual TLS (mTLS) is an extension of TLS that requires both parties (client and server) to present their certificates to each other during the handshake process. This way, both parties can verify each other's identity and establish a secure connection. The authentication of the server happens before the authentication of the client, as the server sends its certificate first and then requests the client's certificate. References:
https://docs.mulesoft.com/mule-runtime/4.3/tls-configuration#mutual-authentication