Add custom SearchWP Extension to Extensions dropdown in settings UI

searchwp-customizations.php

<?php

// Add custom SearchWP Extension to Extensions dropdown in settings UI.

// SearchWP Extensions must be a class that starts with "SearchWP" 
// immediately followed by your unique class name.
class SearchWPMyExtension {
  
  function __construct() {
    add_filter( 'searchwp\extensions', function( $extensions ) {
      // Following the class name rule, the array key is your unique
      // class name _excluding_ the required "SearchWP" prefix.
      $extensions['MyExtension'] = __FILE__;

      return $extensions;
    } );
  }
  
  // Render Extension view.
  function view() {
    ?>
    <h3>My Extension</h3>
    <?php
  }
    
}

new MySearchWPExtension();