Where is the client log?

Where do client/designer log messages go? Is there anywhere I can see stdout/stderr? What about uncaught exceptions?

I’ve setup log4j with the following, but I still can’t find the message anywhere:

public class ClientHook extends AbstractClientModuleHook {
    private static final Logger log = Logger.getLogger(ClientHook.class);

    public void startup(ClientContext context, LicenseState licence) throws Exception {
        log.info("ClientModuleHook startup");


It’s under help->diagnositics in the client menu: