default jupyterhub python kernel should be Python 3 not Mantid Python

[moellep]

When you open a new python notebook on jupyter, it shows a "Select Kernel" dialog with "Mantid Python" preselected. It should show "Python 3" as the default.

This seems to be repeatable when you open a notebook which has a different kernelspec and language_info:

$ git diff shadow.ipynb 
diff --git a/docs/source/notebooks/shadow.ipynb b/docs/source/notebooks/shadow.ipynb
index c7ef576..4fd5b8e 100644
--- a/docs/source/notebooks/shadow.ipynb
+++ b/docs/source/notebooks/shadow.ipynb
@@ -93,7 +93,7 @@
   "kernelspec": {
    "display_name": "Python 3",
    "language": "python",
-   "name": "python3"
+   "name": "py3"
   },
   "language_info": {
    "codemirror_mode": {
@@ -105,7 +105,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.7"
+   "version": "3.7.2"
   }
  },

[e-carlin]

I tried https://github.com/jupyter/notebook/issues/3338#issuecomment-668168649 to no avail. Maybe there is a jupyterlab setting.

[robnagler]

My guess is there is no default kernel for this case, because it's unusual. I don't think this would be a jupyterlab issue but something in notebook.