#23: wp_sprintf_l

wp_sprintf_l.php

<?php
/**
 * Remove use of Oxford/serial comma at the end of taxonomy lists
 * 
 * @param array $separators The array of defaul list item separators.
 *
 * @return array The filtered list of list separators.
 */
function wpdocs_no_oxford_comma( $separators ) {
	// Replaces __( ', and ' )
	$separators['between_last_two'] = __( ' and ' );
	return $separators;
}
add_filter( 'wp_sprintf_l', 'wpdocs_no_oxford_comma' );