User-Friendly Labeling for WP Custom Post Type

gistfile1.php

/* ==================
 * User-Friendly Labeling
 */ // Sometimes you don't want to remove, say, the editor
    // from the post-type, but maybe you just want to 
    // call it something different.
    
function post_type_label_rewrite( $translation, $text, $domain ) {
  global $post;
  
  if ( !isset( $post->post_type ) ) { return $translation; }
	
  $translations = &get_translations_for_domain($domain);
  
	$translation_array = array();
	switch ( $post->post_type ) {
		
    case 'custom_post_type': // Enter the post-type slug here
      $translation_array = array(
		
        'Excerpt' => 'A brief, friendly summary.'
		
      );			
    break;
	}
 
	if ( array_key_exists( $text, $translation_array ) ) { return $translations->translate( $translation_array[$text] ); }
  
  return $translation;
  }
  
add_filter('gettext', 'library_academy_label_rewrite', 10, 4);