How can I programmatically get the admin theme Similar question to How can I programmatically get the theme name? and How do I programmatically change the admin theme?. 

I want to simply obtain  the current admin theme machine name and human name, even when I might not be on a page where the admin theme is enabled as the active theme.

This information doesn't appear to be directly accessible via the ThemeManager class.
This is config and you can get it with the following snippet.

$admin_theme = \Drupal::config('system.theme')-&gt;get('admin');
$admin_theme_name = \Drupal::service('theme_handler')-&gt;getName($admin_theme);


Or with Drush:

drush cget system.theme admin