This is how I use to debug any twig template and it's variables.
Just include into your twig template and pass variable = object | array | null
{% partial 'debug' variable=post %}{% if this.environment != ('production' or 'prod' ) %}
<ol>
{% if variable is defined %}
{% set debugItem = variable %}
{% else %}
{% set debugItem = _context %}
{% endif %}
{% if debugItem is iterable %}
{% for key, values in debugItem %}
<li><b>{{ key }}</b></li>
<ol>
{% if values is iterable %}
...
