If you want to e.g. send a report for any unexpected errors in your Process, you can configure a Subprocess that gets called if an error is thrown but is not handled in the Process.
Please note that any return value from the Subprocess called on an unhandled error will be ignored. You can only use it to e.g. send an email about the error, not to return a custom error response to the caller of the main Process. If you want to return a custom error response, you need to wrap your Process shapes in a Scope, add a custom error handler to it, and send your custom error from there.
You can configure the Subprocess to call on an unhandled error from the Process settings side panel.
Also note you need to explicitly pass the error and any other details as parameters to the Subprocess. To pass the exception details to the error handling Subprocess, you must use the #var.error reference.
