Drupal 8 Display True/False instead 0/1 on checkbox value in ConfigFormBase
In drupal8, you can easily handle this from "Manage Display" of your content type.


  Go to /admin/structure/types/manage/article/display
  Select your "view_mode". Ex- Default.





  Go to the boolean field and click on its settings icon which is placed at atmost right side of the field.
  Change the output format to "True/False".




Hope, this works for you.