How to use hovertemplatesrc

I see that they are hovertemplatesrc https://plot.ly/python/reference/#scattermapbox-hovertextsrc
So,I want how to use it. I working on sankey and want to add more information from the list I have to the hovertemplate.
https://codepen.io/thanaphat-areechitsakul/pen/moqZpX

Here’s one example: https://codepen.io/nicolaskruchten/pen/QJgbxo?editors=0010

Let us know if you’re looking for something more specific.

I’d like to see an example of hovertemplatesrc, in the link you’ve shared it is not used.

Saludos