Can I ask questions about backbone.js in Drupal 8, for example "How can I create a model backbone with data from drupalSetting?" or "Best practice to create and use namespace.js in Backbone"?
If the question revolves around the integration of backbone and Drupal, it's perfectly valid to ask the question here.
If the question was about doing something in Backbone, you should go to StackOverflow instead.
Example of OK question.
How can provide data for a Backbone model from the drupalSettings global JS object
I am building a single page application in Drupal, using backbone and ...
Example of question you shouldn't ask here:
How do I load data into a backbone model via Rest in Drupal
I am building a single page application in Drupal, using backbone and have issues getting backbone load models from the data fetched from a Drupal 8 site...
Note that even though the project is in Drupal, the question is not related to Drupal in anyway (since the rest is working just fine), but the issue is debugging / using backbone correctly, which is off topic here.
I think it is valid to ask since it may be related to the best practise of Drupal.