Equivalent class for Mage_Widget_Block_Interface in magento2

Question

What is the equivalent class for Mage_Widget_Block_Interface in Magento2

I need to

class Vendor_Module_Block_Related_Search extends Mage_Core_Block_Template implements Mage_Widget_Block_Interface
{
   ...
}

in Magento2

Answer 1

You can get it from here,

app/code/vendor/magento/module-widget/Block/BlockInterface.php

You can get it example of core file,

app/code/vendor/magento-sales/Block/Widget/Guest/Form.php file