https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Theme%21Icon%21IconExtractorBase.php/11.x
IconExtractorBase.php | Drupal API
phpdrupalapi
https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Theme%21Icon%21IconExtractorBase.php/class/IconExtractorBase/11.x
class IconExtractorBase | Drupal API
classdrupalapi