All the details are documented at How to deploy static files | Django documentation | Django and Settings | Django documentation | Django
That’s because you’re telling it to do that:
Your STATIC_URL setting is used in the static tag in your template as a prefix to the static file identified as the parameter of that tag.
For example, you have:
This means that something like:
{% static 'css/file.css' %}
is going to end up rendering as:
staticfiles/bands_ratings/css/file.css
Note from the docs for STATIC_URL:
It must end in a slash if set to a non-empty value.