Externd/Override jupyterlab default error messages

Hi all,

I am trying to change the default messages returned by jupyterlab without any luck. I am not very experienced with jupyterlab but I have read tutorials and I have a good understanding on how to write an extension (e.g. GitHub - jupyterlab/extension-examples: JupyterLab Extensions by Examples) but I am not sure how to extend/override the default error messages. This is an example of what I would like to achieve.

I start the server and I create 2 notebooks. After killing the server I receive messages like:

As mentioned here

this the place where of one of the messages I would like to extend/override lives.

I have searched extensively but I couldn’t find any hints whether this is doable (and how this could be done if doable). I have managed to create a simple extension but I can’t see how to extend/override a default behaviour/widget.

Can we override/extend the default dialogue messages that appear in different occasions?

Many thanks,