I'm guessing, no where. At least I don't see it in Chrome's JavaScript console or the Eclipse console. Is GWT.log() ignored|optimized out in Super Dev Mode?
If GWT.log() is unavailable, I guess I should take a stab at GWT's client side logging. However I prefer the simplicity of GWT.log().
Even if so, I'm hooked on Super Dev Mode. I got fed up with apps that run unreliably or not at all with the Chrome plugin, and decided to give Super Dev Mode a try. In addition, I've recently switched from ant to maven, and discovered the gwt:run-codeserver goal in the Codehaus gwt-maven-plugin. This goal makes running Super Dev Mode a snap.