To invoke multiple HTTP APIs in parallel and roll back failed requests in sequence, the developer should use a Scatter-Gather router as a central Saga orchestrator for all API requests with compensating actions for failing routes. A Scatter-Gather router executes multiple routes concurrently and aggregates the results. A Saga orchestrator coordinates a series of actions across different services and handles failures by executing compensating actions. Therefore, using a Scatter-Gather router as a Saga orchestrator allows invoking multiple HTTP APIs in parallel and rolling back any failed requests in sequence. References:
https://docs.mulesoft.com/mule-runtime/4.3/scatter-gather-concepthttps://docs.mulesoft.com/mule-runtime/4.3/sa

When working with correlation IDs, the HTTP Listener generates correlation IDs unless a correlation ID is received in the HTTP request. In that case, it propagates the received correlation ID throughout the flow execution. Correlation IDs are used to track events across different flows or applications.
References:https://docs.mulesoft.com/mule-runtime/4.3/about-mule-message#message-attributes

Explanation
Based on the code snippet and MUnit test case below, when the MUnit test case is executed, the expected result is that the test case fails with an assertion error. This is because the assert-equals processor compares two values for equality, and fails if they are not equal. In this case, the expected value is 'Hello World', but the actual value returned by the implementation flow is 'Hello Mule'. Therefore, the assertion fails and an error is thrown. References: https://docs.mulesoft.com/munit/2.3/assert-equals-processor

To enable mTLS authentication for HTTP Listener, the developer needs to set an appropriate keystore and truststore configuration for the listener. The keystore contains the certificate and private key of the Mule application that are used to prove its identity to clients. The truststore contains the certificates of trusted clients that are allowed to access the Mule application.References:https://docs.mulesoft.com/mule-runtime/4.3/tls-configuration#mutual-authentication