Drupal 8.x

Hello,
I am trying to do some theming for Drupal 8 and was trying to understand what would be the best way to understand what theme is being used on any given page. I remember using theme developer module in D7 and later doing dpm of the page array after theme developer started having issues.

1. Is there any helper module for D8, if so where can I learn to use them?
2. If there are no contrib modules, what other options do I have?

I’m trying to simply add a read-only field which will display phone numbers to contact in lieu of sending the form/email. I can create fields easily, of course, but am not sure where to set these to read-only rather than fields the user can enter into. In other words, another words, just like the my email address field works.

I’d also like to remove the preview button. I’ve tried to hide the preview field, but that didn’t accomplish this.

Any help on both items would be appreciated!

I've found a few Drupal 7 related answers for this but none of them fix my issue. It's really simple to recreate it. I'm having a hard time explaining this so I'll do my best below with an example.

I have a content type, team. This has fields for team name, city, and players. Name and city are text fields and can be ignored for the purposes of this example. Players is an unlimited value entity reference field to a player content type.

I'm wanting to put an iframe into a sidebar of drupal 8 . I installed the iframe module, and enabled.
Added new content > Iframe field . Enter the url for supersaas my schedule so something along line of http://supersaas.com/schedule/name/schedulename and a width and height for iframe, save and publish.

Hi all,
I should send emails from a Drupal7 site with different Smtp accounts (not only the sender address) depending on such user settings.
Which is the best way to implement this?
Which hook should I modify?

Thank you

claudio

I am using Field Groups on Fields within a content type. Rather than display all grouped Variables In a Twig template as individual fields using machine names eg: {{ content.field_cars }}, how can I display ALL fields within a group?

Structure example:

field_cars
  field_black
  field_red
  field_white
field_trucks
  field_black
  field_red
  field_white