How can I trigger a Drupal Core action without writing any PHP code? On my D8 site I have configured an action of type "Send email" using the Drupal Core "Actions" module (module can be installed under "Administration > Extend"). I want this Drupal Core action to trigger when a new comment is submitted.

In D7 there was another Drupal Core module named "Trigger" which allowed me to configure the desired trigger. In D8 there's no longer a "Trigger" module, nor can I find any other means to configure any Drupal Core action triggers. In the D8 docs I have found this not-very-helpful paragraph: 


  In D7, there are triggers defined, supporting the core Trigger module. This is not supported in D8.


My general question therefore is: How can I configure a D8 site to trigger an action that was defined via the Drupal Core module "Actions" when a certain event occurs? Specifically in my case: How can I trigger a "send email" action when a comment is submitted?

As the title of this question mentions, I don't want to write PHP code to achieve this. I am willing to install a stable third-party module, though, as long as it cooperates with the Drupal Core "Actions" module.

In a wider sense, I am trying to understand what the Drupal Core "Actions" module does. To me, the module seems to be quite useless if as a site admin I cannot configure triggers for its actions.
In your specific case the commment notify module would be helpful. 

From description, 


  Comment Notify is a lightweight tool to send notification e-mails to visitors about new, published comments on pages where they have commented. Comment Notify works for both registered and anonymous users.


Otherwise is could be done using Rules I think.