This is an extension.

dev_mode/package.json

@@ -34,6 +34,7 @@
     "@jupyterlab/fileeditor-extension": "^1.0.0-alpha.9",
     "@jupyterlab/help-extension": "^1.0.0-alpha.9",
     "@jupyterlab/htmlviewer-extension": "^1.0.0-alpha.10",
+    "@jupyterlab/hub-extension": "^1.0.0-alpha.8",
     "@jupyterlab/imageviewer": "^1.0.0-alpha.9",
     "@jupyterlab/imageviewer-extension": "^1.0.0-alpha.9",
     "@jupyterlab/inspector-extension": "^1.0.0-alpha.9",
@@ -130,6 +131,7 @@
       "@jupyterlab/fileeditor-extension": "",
       "@jupyterlab/help-extension": "",
       "@jupyterlab/htmlviewer-extension": "",
+      "@jupyterlab/hub-extension": "",
       "@jupyterlab/imageviewer-extension": "",
       "@jupyterlab/inspector-extension": "",
       "@jupyterlab/launcher-extension": "",
@@ -225,6 +227,7 @@
       "@jupyterlab/fileeditor-extension": "../packages/fileeditor-extension",
       "@jupyterlab/help-extension": "../packages/help-extension",
       "@jupyterlab/htmlviewer-extension": "../packages/htmlviewer-extension",
+      "@jupyterlab/hub-extension": "../packages/hub-extension",
       "@jupyterlab/imageviewer-extension": "../packages/imageviewer-extension",
       "@jupyterlab/inspector-extension": "../packages/inspector-extension",
       "@jupyterlab/javascript-extension": "../packages/javascript-extension",

packages/hub-extension/package.json

@@ -32,8 +32,7 @@
     "@jupyterlab/application": "^1.0.0-alpha.9",
     "@jupyterlab/apputils": "^1.0.0-alpha.9",
     "@jupyterlab/coreutils": "^3.0.0-alpha.9",
-    "@jupyterlab/mainmenu": "^1.0.0-alpha.9",
-    "@phosphor/widgets": "^1.7.0"
+    "@jupyterlab/mainmenu": "^1.0.0-alpha.9"
   },
   "devDependencies": {
     "rimraf": "~2.6.2",
@@ -41,5 +40,8 @@
   },
   "publishConfig": {
     "access": "public"
+  },
+  "jupyterlab": {
+    "extension": true
   }
 }