Ticket #36818: export.diff

export.php

@@ -534 +534 @@
                          */
                         if ( apply_filters( 'wxr_export_skip_postmeta', false, $meta->meta_key, $meta ) )
                                 continue;
+                        
+                        /**
+                         * Filter for modifying post meta before it is exported.
+                         *
+                         * @since 4.6.0
+                         *
+                         * @param string $meta_value     Current meta value.
+                         * @param object $meta           Current meta object.
+                         * @param object $post           Current post object.
+                         */
+                        $meta->meta_value = apply_filters( 'wxr_export_postmeta', $meta->meta_value, $meta, $post );
                 ?>
                 <wp:postmeta>
                         <wp:meta_key><?php echo wxr_cdata( $meta->meta_key ); ?></wp:meta_key>