'site_frontpage' variable default value changed to 'user'

The default value of the 'site_frontpage' system variable, which configures the site's front page path, was changed from 'node' to 'user', because Node module became optional.

Drupal 7:

$is_front_page = ($_GET['q'] == variable_get('site_frontpage', 'node'));

Drupal 8:

$is_front_page = ($_GET['q'] == variable_get('site_frontpage', 'user'));

If you want to restore the front page to 'node' in an installation profile, you may do so by:

  // Set front page to "node".
  Drupal::config('system.site')->set('page.front', 'node')->save();