Add Post Author to Recent Post Widgets Extended (RPWE) WordPress plugin output (uses Simple HTML DOM PHP [1.9.1 here] to aid in the HTML traversing & insertion])

rpwe-add-author.php

<?php
// Add Simple HTML DOM for PHP-based HTML/DOM Traversal
if(!function_exists('str_get_html')){
  include 'include/simple_html_dom.php';
}

// Add Author info to Recent Post Widgets Extended output (add before date)
function add_author_to_rpwe_markup($html,$args){
  $html = str_get_html($html);
  foreach($html->find('.rpwe-title a') as $title_link){
    $permalink = $title_link->href;
    $post_id = url_to_postid($permalink);
    $author_id = get_post_field( 'post_author', $post_id );
    $author_display_name = get_the_author_meta( 'display_name', $author_id );
    $title_tag = $title_link->parent();
    $post_element = $title_tag->parent();
    foreach($post_element->find('.rpwe-time') as $time_element){
      $time_element_html = $time_element->outertext;
      $time_element->outertext = '<span class="rpwe-author">'.$author_display_name.'</span> '.$time_element_html;
    }
  }
  $html_output = $html; // Convert back to string
  return $html_output;
}
add_filter('rpwe_markup','add_author_to_rpwe_markup',10,2);