What does a dash do in a block declaration in Twig?

Question

symfony

In symfony templates (for example, in form_div_layout.html.twig ) I came across this code:

{% block example -%}
...
{%- endblock example %}

What are these dashes for? In my opinion, without them, twig works exactly the same.

Answer 1

twig.sensiolabs.org/doc/templates.html#whitespace-...
These dashes can be put in general for all blocks, for if, for, etc.