https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Theme%21ThemeInitialization.php/function/ThemeInitialization%3A%3AgetActiveThemeByName/9
function ThemeInitialization::getActiveThemeByName | Drupal API
functiondrupalapi
https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Theme%21ThemeInitialization.php/11.x
ThemeInitialization.php | Drupal API
phpdrupalapi