WordPress at a glance
function is not described

get_trackback_url() WP 1.5.0

Retrieve The current post's trackback URL.

There is a check to see if permalink's have been enabled and if so, will retrieve the pretty path. If permalinks weren't enabled, the ID of the current post is used and appended to the correct page to go to.

Hooks in function
Return

String. The trackback URL after being filtered.

Usage

get_trackback_url();

Code of get trackback url: wp-includes/comment-template.php WP 5.2.1

<?php
function get_trackback_url() {
	if ( '' != get_option( 'permalink_structure' ) ) {
		$tb_url = trailingslashit( get_permalink() ) . user_trailingslashit( 'trackback', 'single_trackback' );
	} else {
		$tb_url = get_option( 'siteurl' ) . '/wp-trackback.php?p=' . get_the_ID();
	}

	/**
	 * Filters the returned trackback URL.
	 *
	 * @since 2.2.0
	 *
	 * @param string $tb_url The trackback URL.
	 */
	return apply_filters( 'trackback_url', $tb_url );
}