How to split region block render?
You can iterate through the blocks in this way:

{% for block_key, block in elements if block_key|first != '#' %}
  &lt;b&gt;{{ block_key }}: &lt;/b&gt;
  {{ block }}
{% endfor %}


If you just need to know the blocks that are present in a given region, you could use this:

{{ dump(elements|keys) }}


Then you can print each block as:

{{ elements.key }}