theme_get_registry($complete = TRUE)
Gets the theme registry.
Parameters
bool $complete: Optional boolean to indicate whether to return the complete theme registry array or an instance of the Drupal\Core\Utility\ThemeRegistry class. If TRUE, the complete theme registry array will be returned. This is useful if you want to foreach over the whole registry, use array_* functions or inspect it in a debugger. If FALSE, an instance of the Drupal\Core\Utility\ThemeRegistry class will be returned, thi