Source

File: wp-includes/deprecated.php

function make_url_footnote( $content ) {
	_deprecated_function( __FUNCTION__, '2.9.0', '' );
	preg_match_all( '/<a(.+?)href=\"(.+?)\"(.*?)>(.+?)<\/a>/', $content, $matches );
	$links_summary = "\n";
	for ( $i = 0, $c = count( $matches[0] ); $i < $c; $i++ ) {
		$link_match = $matches[0][$i];
		$link_number = '['.($i+1).']';
		$link_url = $matches[2][$i];
		$link_text = $matches[4][$i];
		$content = str_replace( $link_match, $link_text . ' ' . $link_number, $content );
		$link_url = ( ( strtolower( substr( $link_url, 0, 7 ) ) != 'http://' ) && ( strtolower( substr( $link_url, 0, 8 ) ) != 'https://' ) ) ? get_option( 'home' ) . $link_url : $link_url;
		$links_summary .= "\n" . $link_number . ' ' . $link_url;
	}
	$content  = strip_tags( $content );
	$content .= $links_summary;
	return $content;
}