https://api.drupal.org/api/drupal/core%21modules%21views%21src%21Plugin%21views%21filter%21InOperator.php/property/InOperator%3A%3AvalueFormType/11.x
InOperator::$valueFormType | Drupal API
drupalapi
https://api.drupal.org/api/drupal/core%21modules%21views%21src%21Plugin%21views%21filter%21InOperator.php/function/InOperator%3A%3AreduceValueOptions/9
function InOperator::reduceValueOptions | Drupal API
functiondrupalapi
https://api.drupal.org/api/drupal/core%21modules%21views%21src%21Plugin%21views%21filter%21InOperator.php/function/InOperator%3A%3AoperatorOptions/8.9.x
function InOperator::operatorOptions | Drupal API
functiondrupalapi