Aid debugging future leaks

src/index.ts

@@ -261,6 +261,7 @@ window.addEventListener('load', async () => {
         floorMeshes: () => activeFloorMeshes,
         touchableMeshes: () => activeTouchableMeshes,
     });
+    (window as any).E = runningEngine;
     Dataspace.boot(ds => {
         html.boot(ds);
         timer.boot(ds);