The problem

Flask-Bootstrap does not have a footer block by default. The way of implementing one is covered in the FAQ but I think this is fairly misleading.

From the example given, it is suggested that a new template should be created as base-with-footer.html, like:

{% extends "bootstrap/base.html" %}

{%- block content %}
{{super()}}
{%- block footer %}
<footer>&copy; 2016 Awesome, Inc.</footer>
{%- endblock footer %}
{%- endblock content %}

Any time you want to extend from the base-with-footer.html, you'll have to call super() inside the content block. This is ugly and beats DRY.

I suggest a different approach: use footer outside the content block.

For the template in my_custom_blueprint/my_base.html

{% extends "bootstrap/base.html" %}
{# stuff happens here, like overrides of the original template in https://github.com/mbr/flask-bootstrap/blob/master/flask_bootstrap/templates/bootstrap/base.html  #}
{% block content %}<p>Hello World!</p>{%- endblock content %}
{% block footer %}{%- endblock footer %}

Now in my_base_with_footer.html

{% extends "my_custom_blueprint/my_base.html" %}
{% block footer %}<p>Here goes your footer!</p>{%- endblock footer %}

With this approach you can reuse any of the blocks from the base without having to call super() each time you need to write in contents. You just have to extend from the template with the footer.