(Drupal 8) Views template override confusion about available variables

I have created a Views' block template override. Have tested and debugged it and it works.
I mean it is loaded successfully. I have a confusion though about how to loop
through records.

In Views version of Drupal 7 it was easy to get everything loop. But in Drupal 8 due to its advancement in terms of template and Entity expansion, it need some bit of more knowledge.

When I do the following, the records get printed:

<?php
{% for row in rows %}
   {{ row.content }}
{% endfor %}
?>

Though I want to have full access to each individual field, and print them as I like:

<?php
// for example
{% for row in rows %}
   {{ row.node_title }}
{% endfor %}
?>

Am I obliged to use preprocessor function? Isn't there a ready to use array which yet has not been processed into row.content?

Thanks in advance