Index: src/wp-includes/general-template.php
===================================================================
--- src/wp-includes/general-template.php	(revision 28656)
+++ src/wp-includes/general-template.php	(working copy)
@@ -836,13 +836,20 @@
 	if ( !empty($title) )
 		$prefix = " $sep ";
 
+	/**
+	 * Filter the parts of the document title.
+	 *
+	 * @since 4.0.0
+	 *
+	 * @param array $title_array Parts of the document title.
+	 */
+	$title_array = apply_filters( 'wp_title_parts', explode( $t_sep, $title ) );
+
  	// Determines position of the separator and direction of the breadcrumb
 	if ( 'right' == $seplocation ) { // sep on right, so reverse the order
-		$title_array = explode( $t_sep, $title );
 		$title_array = array_reverse( $title_array );
 		$title = implode( " $sep ", $title_array ) . $prefix;
 	} else {
-		$title_array = explode( $t_sep, $title );
 		$title = $prefix . implode( " $sep ", $title_array );
 	}