https://api.drupal.org/api/drupal/core%21modules%21search%21src%21Form%21SearchPageForm.php/11.x
SearchPageForm.php | Drupal API
phpdrupalapi
https://api.drupal.org/api/drupal/core%21modules%21search%21src%21Form%21SearchPageForm.php/function/SearchPageForm%3A%3AgetFormId/10
function SearchPageForm::getFormId | Drupal API
functiondrupalapi